From d6e135c0b53bb0871f1026a76aeff8812d81498e Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Sun, 2 Feb 2020 13:14:54 +0800
Subject: [PATCH 1/9] separate problems and answers

---
 .gitignore                                    |   1 +
 src/{problem.rs => fetcher.rs}                |   0
 src/lib.rs                                    | 239 +-----------------
 src/main.rs                                   |  16 +-
 src/problem/mod.rs                            |   0
 src/solution/mod.rs                           | 237 +++++++++++++++++
 .../s0001_two_sum.rs}                         |   0
 .../s0002_add_two_numbers.rs}                 |   2 +-
 .../s0003_longest_substring.rs}               |   0
 .../s0004_median_of_two_sorted_arrays.rs}     |   0
 .../s0005_longest_palindromic_substring.rs}   |   0
 .../s0006_zigzag_conversion.rs}               |   0
 .../s0007_reverse_integer.rs}                 |   0
 .../s0008_string_to_integer_atoi.rs}          |   0
 .../s0009_palindrome_number.rs}               |   0
 .../s0010_regular_expression_matching.rs}     |   0
 .../s0011_container_with_most_water.rs}       |   0
 .../s0012_integer_to_roman.rs}                |   0
 .../s0013_roman_to_integer.rs}                |   0
 .../s0014_longest_common_prefix.rs}           |   0
 src/{n0015_3sum.rs => solution/s0015_3sum.rs} |   0
 .../s0016_3sum_closest.rs}                    |   0
 ..._letter_combinations_of_a_phone_number.rs} |   0
 src/{n0018_4sum.rs => solution/s0018_4sum.rs} |   0
 ...s0019_remove_nth_node_from_end_of_list.rs} |   2 +-
 .../s0020_valid_parentheses.rs}               |   0
 .../s0021_merge_two_sorted_lists.rs}          |   2 +-
 .../s0022_generate_parentheses.rs}            |   0
 .../s0023_merge_k_sorted_lists.rs}            |   2 +-
 .../s0024_swap_nodes_in_pairs.rs}             |   2 +-
 .../s0025_reverse_nodes_in_k_group.rs}        |   2 +-
 ...26_remove_duplicates_from_sorted_array.rs} |   0
 .../s0027_remove_element.rs}                  |   0
 .../s0028_implement_strstr.rs}                |   0
 .../s0029_divide_two_integers.rs}             |   0
 ...string_with_concatenation_of_all_words.rs} |   0
 .../s0031_next_permutation.rs}                |   0
 .../s0032_longest_valid_parentheses.rs}       |   0
 .../s0033_search_in_rotated_sorted_array.rs}  |   0
 ...st_position_of_element_in_sorted_array.rs} |   0
 .../s0035_search_insert_position.rs}          |   0
 .../s0036_valid_sudoku.rs}                    |   0
 .../s0037_sudoku_solver.rs}                   |   0
 .../s0038_count_and_say.rs}                   |   0
 .../s0039_combination_sum.rs}                 |   0
 .../s0040_combination_sum_ii.rs}              |   0
 .../s0041_first_missing_positive.rs}          |   0
 .../s0042_trapping_rain_water.rs}             |   0
 .../s0043_multiply_strings.rs}                |   0
 .../s0044_wildcard_matching.rs}               |   0
 .../s0045_jump_game_ii.rs}                    |   0
 .../s0046_permutations.rs}                    |   0
 .../s0047_permutations_ii.rs}                 |   0
 .../s0048_rotate_image.rs}                    |   0
 .../s0049_group_anagrams.rs}                  |   0
 .../s0050_powx_n.rs}                          |   0
 .../s0051_n_queens.rs}                        |   0
 .../s0052_n_queens_ii.rs}                     |   0
 .../s0053_maximum_subarray.rs}                |   0
 .../s0054_spiral_matrix.rs}                   |   0
 .../s0055_jump_game.rs}                       |   0
 .../s0056_merge_intervals.rs}                 |   0
 .../s0057_insert_interval.rs}                 |   0
 .../s0058_length_of_last_word.rs}             |   0
 .../s0059_spiral_matrix_ii.rs}                |   0
 .../s0060_permutation_sequence.rs}            |   0
 .../s0061_rotate_list.rs}                     |   2 +-
 .../s0062_unique_paths.rs}                    |   0
 .../s0063_unique_paths_ii.rs}                 |   0
 .../s0064_minimum_path_sum.rs}                |   0
 .../s0065_valid_number.rs}                    |   0
 .../s0066_plus_one.rs}                        |   0
 .../s0067_add_binary.rs}                      |   0
 .../s0068_text_justification.rs}              |   0
 .../s0069_sqrtx.rs}                           |   0
 .../s0070_climbing_stairs.rs}                 |   0
 .../s0071_simplify_path.rs}                   |   0
 .../s0072_edit_distance.rs}                   |   0
 .../s0073_set_matrix_zeroes.rs}               |   0
 .../s0074_search_a_2d_matrix.rs}              |   0
 .../s0075_sort_colors.rs}                     |   0
 .../s0076_minimum_window_substring.rs}        |   0
 .../s0077_combinations.rs}                    |   0
 .../s0078_subsets.rs}                         |   0
 .../s0079_word_search.rs}                     |   0
 ...remove_duplicates_from_sorted_array_ii.rs} |   0
 ...0081_search_in_rotated_sorted_array_ii.rs} |   0
 ..._remove_duplicates_from_sorted_list_ii.rs} |   2 +-
 ...083_remove_duplicates_from_sorted_list.rs} |   2 +-
 .../s0084_largest_rectangle_in_histogram.rs}  |   0
 .../s0085_maximal_rectangle.rs}               |   0
 .../s0086_partition_list.rs}                  |   2 +-
 .../s0087_scramble_string.rs}                 |   0
 .../s0088_merge_sorted_array.rs}              |   0
 .../s0089_gray_code.rs}                       |   0
 .../s0090_subsets_ii.rs}                      |   0
 .../s0091_decode_ways.rs}                     |   0
 .../s0092_reverse_linked_list_ii.rs}          |   2 +-
 .../s0093_restore_ip_addresses.rs}            |   0
 .../s0094_binary_tree_inorder_traversal.rs}   |   2 +-
 .../s0095_unique_binary_search_trees_ii.rs}   |   2 +-
 .../s0096_unique_binary_search_trees.rs}      |   0
 .../s0097_interleaving_string.rs}             |   0
 .../s0098_validate_binary_search_tree.rs}     |   2 +-
 .../s0099_recover_binary_search_tree.rs}      |   2 +-
 .../s0100_same_tree.rs}                       |   2 +-
 .../s0101_symmetric_tree.rs}                  |   2 +-
 ...0102_binary_tree_level_order_traversal.rs} |   2 +-
 ...nary_tree_zigzag_level_order_traversal.rs} |   2 +-
 .../s0104_maximum_depth_of_binary_tree.rs}    |   2 +-
 ...ee_from_preorder_and_inorder_traversal.rs} |   2 +-
 ...e_from_inorder_and_postorder_traversal.rs} |   2 +-
 ...7_binary_tree_level_order_traversal_ii.rs} |   2 +-
 ...ert_sorted_array_to_binary_search_tree.rs} |   2 +-
 ...vert_sorted_list_to_binary_search_tree.rs} |   4 +-
 .../s0110_balanced_binary_tree.rs}            |   2 +-
 .../s0111_minimum_depth_of_binary_tree.rs}    |   2 +-
 .../s0112_path_sum.rs}                        |   2 +-
 .../s0113_path_sum_ii.rs}                     |   2 +-
 ...114_flatten_binary_tree_to_linked_list.rs} |   2 +-
 .../s0115_distinct_subsequences.rs}           |   0
 .../s0118_pascals_triangle.rs}                |   0
 .../s0119_pascals_triangle_ii.rs}             |   0
 .../s0120_triangle.rs}                        |   0
 .../s0121_best_time_to_buy_and_sell_stock.rs} |   0
 ...122_best_time_to_buy_and_sell_stock_ii.rs} |   0
 ...23_best_time_to_buy_and_sell_stock_iii.rs} |   0
 .../s0124_binary_tree_maximum_path_sum.rs}    |   2 +-
 .../s0125_valid_palindrome.rs}                |   0
 .../s0126_word_ladder_ii.rs}                  |   0
 .../s0127_word_ladder.rs}                     |   0
 .../s0128_longest_consecutive_sequence.rs}    |   0
 .../s0129_sum_root_to_leaf_numbers.rs}        |   2 +-
 .../s0130_surrounded_regions.rs}              |   0
 .../s0131_palindrome_partitioning.rs}         |   0
 .../s0132_palindrome_partitioning_ii.rs}      |   0
 .../s0134_gas_station.rs}                     |   0
 .../s0135_candy.rs}                           |   0
 .../s0136_single_number.rs}                   |   0
 .../s0137_single_number_ii.rs}                |   0
 .../s0139_word_break.rs}                      |   0
 .../s0140_word_break_ii.rs}                   |   0
 .../s0143_reorder_list.rs}                    |   2 +-
 .../s0144_binary_tree_preorder_traversal.rs}  |   2 +-
 .../s0145_binary_tree_postorder_traversal.rs} |   2 +-
 .../s0146_lru_cache.rs}                       |   0
 .../s0147_insertion_sort_list.rs}             |   4 +-
 .../s0148_sort_list.rs}                       |   2 +-
 .../s0149_max_points_on_a_line.rs}            |   4 +-
 ...s0150_evaluate_reverse_polish_notation.rs} |   0
 .../s0151_reverse_words_in_a_string.rs}       |   0
 .../s0152_maximum_product_subarray.rs}        |   0
 ...3_find_minimum_in_rotated_sorted_array.rs} |   0
 ...ind_minimum_in_rotated_sorted_array_ii.rs} |   0
 .../s0155_min_stack.rs}                       |   0
 .../s0162_find_peak_element.rs}               |   0
 .../s0164_maximum_gap.rs}                     |   0
 .../s0165_compare_version_numbers.rs}         |   0
 .../s0166_fraction_to_recurring_decimal.rs}   |   0
 ...s0167_two_sum_ii_input_array_is_sorted.rs} |   0
 .../s0168_excel_sheet_column_title.rs}        |   0
 .../s0169_majority_element.rs}                |   0
 .../s0171_excel_sheet_column_number.rs}       |   0
 .../s0172_factorial_trailing_zeroes.rs}       |   0
 .../s0173_binary_search_tree_iterator.rs}     |   6 +-
 .../s0174_dungeon_game.rs}                    |   0
 .../s0179_largest_number.rs}                  |   0
 .../s0187_repeated_dna_sequences.rs}          |   0
 ...188_best_time_to_buy_and_sell_stock_iv.rs} |   0
 .../s0189_rotate_array.rs}                    |   0
 .../s0198_house_robber.rs}                    |   0
 .../s0199_binary_tree_right_side_view.rs}     |   2 +-
 .../s0200_number_of_islands.rs}               |   0
 .../s0201_bitwise_and_of_numbers_range.rs}    |   0
 .../s0202_happy_number.rs}                    |   0
 .../s0203_remove_linked_list_elements.rs}     |   2 +-
 .../s0204_count_primes.rs}                    |   0
 .../s0205_isomorphic_strings.rs}              |   0
 .../s0206_reverse_linked_list.rs}             |   2 +-
 .../s0207_course_schedule.rs}                 |   0
 .../s0208_implement_trie_prefix_tree.rs}      |   0
 .../s0209_minimum_size_subarray_sum.rs}       |   0
 .../s0210_course_schedule_ii.rs}              |   0
 ..._and_search_word_data_structure_design.rs} |   0
 .../s0212_word_search_ii.rs}                  |   0
 .../s0213_house_robber_ii.rs}                 |   0
 .../s0214_shortest_palindrome.rs}             |   0
 .../s0215_kth_largest_element_in_an_array.rs} |   0
 .../s0216_combination_sum_iii.rs}             |   0
 .../s0217_contains_duplicate.rs}              |   0
 .../s0218_the_skyline_problem.rs}             |   0
 .../s0219_contains_duplicate_ii.rs}           |   0
 .../s0220_contains_duplicate_iii.rs}          |   0
 .../s0221_maximal_square.rs}                  |   0
 .../s0222_count_complete_tree_nodes.rs}       |   2 +-
 .../s0223_rectangle_area.rs}                  |   0
 .../s0224_basic_calculator.rs}                |   0
 .../s0225_implement_stack_using_queues.rs}    |   0
 .../s0226_invert_binary_tree.rs}              |   2 +-
 .../s0227_basic_calculator_ii.rs}             |   0
 .../s0228_summary_ranges.rs}                  |   0
 .../s0229_majority_element_ii.rs}             |   0
 .../s0230_kth_smallest_element_in_a_bst.rs}   |   2 +-
 .../s0231_power_of_two.rs}                    |   0
 .../s0232_implement_queue_using_stacks.rs}    |   0
 .../s0233_number_of_digit_one.rs}             |   0
 .../s0238_product_of_array_except_self.rs}    |   0
 .../s0239_sliding_window_maximum.rs}          |   0
 ...0241_different_ways_to_add_parentheses.rs} |   0
 .../s0242_valid_anagram.rs}                   |   0
 .../s0257_binary_tree_paths.rs}               |   2 +-
 .../s0258_add_digits.rs}                      |   0
 .../s0260_single_number_iii.rs}               |   0
 .../s0263_ugly_number.rs}                     |   0
 .../s0264_ugly_number_ii.rs}                  |   0
 .../s0268_missing_number.rs}                  |   0
 .../s0273_integer_to_english_words.rs}        |   0
 .../s0274_h_index.rs}                         |   0
 .../s0275_h_index_ii.rs}                      |   0
 .../s0279_perfect_squares.rs}                 |   0
 .../s0282_expression_add_operators.rs}        |   0
 .../s0283_move_zeroes.rs}                     |   0
 .../s0287_find_the_duplicate_number.rs}       |   0
 .../s0289_game_of_life.rs}                    |   0
 .../s0290_word_pattern.rs}                    |   0
 .../s0292_nim_game.rs}                        |   0
 .../s0295_find_median_from_data_stream.rs}    |   0
 .../s0299_bulls_and_cows.rs}                  |   0
 .../s0300_longest_increasing_subsequence.rs}  |   0
 .../s0301_remove_invalid_parentheses.rs}      |   0
 .../s0303_range_sum_query_immutable.rs}       |   0
 .../s0304_range_sum_query_2d_immutable.rs}    |   0
 .../s0306_additive_number.rs}                 |   0
 .../s0307_range_sum_query_mutable.rs}         |   0
 ...me_to_buy_and_sell_stock_with_cooldown.rs} |   0
 .../s0310_minimum_height_trees.rs}            |   0
 .../s0312_burst_balloons.rs}                  |   0
 .../s0313_super_ugly_number.rs}               |   0
 .../s0509_fibonacci_number.rs}                |   0
 .../s0704_binary_search.rs}                   |   0
 .../s0969_pancake_sorting.rs}                 |   0
 .../s1018_binary_prefix_divisible_by_5.rs}    |   0
 .../s1046_last_stone_weight.rs}               |   0
 243 files changed, 299 insertions(+), 296 deletions(-)
 rename src/{problem.rs => fetcher.rs} (100%)
 create mode 100644 src/problem/mod.rs
 create mode 100644 src/solution/mod.rs
 rename src/{n0001_two_sum.rs => solution/s0001_two_sum.rs} (100%)
 rename src/{n0002_add_two_numbers.rs => solution/s0002_add_two_numbers.rs} (98%)
 rename src/{n0003_longest_substring.rs => solution/s0003_longest_substring.rs} (100%)
 rename src/{n0004_median_of_two_sorted_arrays.rs => solution/s0004_median_of_two_sorted_arrays.rs} (100%)
 rename src/{n0005_longest_palindromic_substring.rs => solution/s0005_longest_palindromic_substring.rs} (100%)
 rename src/{n0006_zigzag_conversion.rs => solution/s0006_zigzag_conversion.rs} (100%)
 rename src/{n0007_reverse_integer.rs => solution/s0007_reverse_integer.rs} (100%)
 rename src/{n0008_string_to_integer_atoi.rs => solution/s0008_string_to_integer_atoi.rs} (100%)
 rename src/{n0009_palindrome_number.rs => solution/s0009_palindrome_number.rs} (100%)
 rename src/{n0010_regular_expression_matching.rs => solution/s0010_regular_expression_matching.rs} (100%)
 rename src/{n0011_container_with_most_water.rs => solution/s0011_container_with_most_water.rs} (100%)
 rename src/{n0012_integer_to_roman.rs => solution/s0012_integer_to_roman.rs} (100%)
 rename src/{n0013_roman_to_integer.rs => solution/s0013_roman_to_integer.rs} (100%)
 rename src/{n0014_longest_common_prefix.rs => solution/s0014_longest_common_prefix.rs} (100%)
 rename src/{n0015_3sum.rs => solution/s0015_3sum.rs} (100%)
 rename src/{n0016_3sum_closest.rs => solution/s0016_3sum_closest.rs} (100%)
 rename src/{n0017_letter_combinations_of_a_phone_number.rs => solution/s0017_letter_combinations_of_a_phone_number.rs} (100%)
 rename src/{n0018_4sum.rs => solution/s0018_4sum.rs} (100%)
 rename src/{n0019_remove_nth_node_from_end_of_list.rs => solution/s0019_remove_nth_node_from_end_of_list.rs} (97%)
 rename src/{n0020_valid_parentheses.rs => solution/s0020_valid_parentheses.rs} (100%)
 rename src/{n0021_merge_two_sorted_lists.rs => solution/s0021_merge_two_sorted_lists.rs} (97%)
 rename src/{n0022_generate_parentheses.rs => solution/s0022_generate_parentheses.rs} (100%)
 rename src/{n0023_merge_k_sorted_lists.rs => solution/s0023_merge_k_sorted_lists.rs} (97%)
 rename src/{n0024_swap_nodes_in_pairs.rs => solution/s0024_swap_nodes_in_pairs.rs} (97%)
 rename src/{n0025_reverse_nodes_in_k_group.rs => solution/s0025_reverse_nodes_in_k_group.rs} (98%)
 rename src/{n0026_remove_duplicates_from_sorted_array.rs => solution/s0026_remove_duplicates_from_sorted_array.rs} (100%)
 rename src/{n0027_remove_element.rs => solution/s0027_remove_element.rs} (100%)
 rename src/{n0028_implement_strstr.rs => solution/s0028_implement_strstr.rs} (100%)
 rename src/{n0029_divide_two_integers.rs => solution/s0029_divide_two_integers.rs} (100%)
 rename src/{n0030_substring_with_concatenation_of_all_words.rs => solution/s0030_substring_with_concatenation_of_all_words.rs} (100%)
 rename src/{n0031_next_permutation.rs => solution/s0031_next_permutation.rs} (100%)
 rename src/{n0032_longest_valid_parentheses.rs => solution/s0032_longest_valid_parentheses.rs} (100%)
 rename src/{n0033_search_in_rotated_sorted_array.rs => solution/s0033_search_in_rotated_sorted_array.rs} (100%)
 rename src/{n0034_find_first_and_last_position_of_element_in_sorted_array.rs => solution/s0034_find_first_and_last_position_of_element_in_sorted_array.rs} (100%)
 rename src/{n0035_search_insert_position.rs => solution/s0035_search_insert_position.rs} (100%)
 rename src/{n0036_valid_sudoku.rs => solution/s0036_valid_sudoku.rs} (100%)
 rename src/{n0037_sudoku_solver.rs => solution/s0037_sudoku_solver.rs} (100%)
 rename src/{n0038_count_and_say.rs => solution/s0038_count_and_say.rs} (100%)
 rename src/{n0039_combination_sum.rs => solution/s0039_combination_sum.rs} (100%)
 rename src/{n0040_combination_sum_ii.rs => solution/s0040_combination_sum_ii.rs} (100%)
 rename src/{n0041_first_missing_positive.rs => solution/s0041_first_missing_positive.rs} (100%)
 rename src/{n0042_trapping_rain_water.rs => solution/s0042_trapping_rain_water.rs} (100%)
 rename src/{n0043_multiply_strings.rs => solution/s0043_multiply_strings.rs} (100%)
 rename src/{n0044_wildcard_matching.rs => solution/s0044_wildcard_matching.rs} (100%)
 rename src/{n0045_jump_game_ii.rs => solution/s0045_jump_game_ii.rs} (100%)
 rename src/{n0046_permutations.rs => solution/s0046_permutations.rs} (100%)
 rename src/{n0047_permutations_ii.rs => solution/s0047_permutations_ii.rs} (100%)
 rename src/{n0048_rotate_image.rs => solution/s0048_rotate_image.rs} (100%)
 rename src/{n0049_group_anagrams.rs => solution/s0049_group_anagrams.rs} (100%)
 rename src/{n0050_powx_n.rs => solution/s0050_powx_n.rs} (100%)
 rename src/{n0051_n_queens.rs => solution/s0051_n_queens.rs} (100%)
 rename src/{n0052_n_queens_ii.rs => solution/s0052_n_queens_ii.rs} (100%)
 rename src/{n0053_maximum_subarray.rs => solution/s0053_maximum_subarray.rs} (100%)
 rename src/{n0054_spiral_matrix.rs => solution/s0054_spiral_matrix.rs} (100%)
 rename src/{n0055_jump_game.rs => solution/s0055_jump_game.rs} (100%)
 rename src/{n0056_merge_intervals.rs => solution/s0056_merge_intervals.rs} (100%)
 rename src/{n0057_insert_interval.rs => solution/s0057_insert_interval.rs} (100%)
 rename src/{n0058_length_of_last_word.rs => solution/s0058_length_of_last_word.rs} (100%)
 rename src/{n0059_spiral_matrix_ii.rs => solution/s0059_spiral_matrix_ii.rs} (100%)
 rename src/{n0060_permutation_sequence.rs => solution/s0060_permutation_sequence.rs} (100%)
 rename src/{n0061_rotate_list.rs => solution/s0061_rotate_list.rs} (94%)
 rename src/{n0062_unique_paths.rs => solution/s0062_unique_paths.rs} (100%)
 rename src/{n0063_unique_paths_ii.rs => solution/s0063_unique_paths_ii.rs} (100%)
 rename src/{n0064_minimum_path_sum.rs => solution/s0064_minimum_path_sum.rs} (100%)
 rename src/{n0065_valid_number.rs => solution/s0065_valid_number.rs} (100%)
 rename src/{n0066_plus_one.rs => solution/s0066_plus_one.rs} (100%)
 rename src/{n0067_add_binary.rs => solution/s0067_add_binary.rs} (100%)
 rename src/{n0068_text_justification.rs => solution/s0068_text_justification.rs} (100%)
 rename src/{n0069_sqrtx.rs => solution/s0069_sqrtx.rs} (100%)
 rename src/{n0070_climbing_stairs.rs => solution/s0070_climbing_stairs.rs} (100%)
 rename src/{n0071_simplify_path.rs => solution/s0071_simplify_path.rs} (100%)
 rename src/{n0072_edit_distance.rs => solution/s0072_edit_distance.rs} (100%)
 rename src/{n0073_set_matrix_zeroes.rs => solution/s0073_set_matrix_zeroes.rs} (100%)
 rename src/{n0074_search_a_2d_matrix.rs => solution/s0074_search_a_2d_matrix.rs} (100%)
 rename src/{n0075_sort_colors.rs => solution/s0075_sort_colors.rs} (100%)
 rename src/{n0076_minimum_window_substring.rs => solution/s0076_minimum_window_substring.rs} (100%)
 rename src/{n0077_combinations.rs => solution/s0077_combinations.rs} (100%)
 rename src/{n0078_subsets.rs => solution/s0078_subsets.rs} (100%)
 rename src/{n0079_word_search.rs => solution/s0079_word_search.rs} (100%)
 rename src/{n0080_remove_duplicates_from_sorted_array_ii.rs => solution/s0080_remove_duplicates_from_sorted_array_ii.rs} (100%)
 rename src/{n0081_search_in_rotated_sorted_array_ii.rs => solution/s0081_search_in_rotated_sorted_array_ii.rs} (100%)
 rename src/{n0082_remove_duplicates_from_sorted_list_ii.rs => solution/s0082_remove_duplicates_from_sorted_list_ii.rs} (94%)
 rename src/{n0083_remove_duplicates_from_sorted_list.rs => solution/s0083_remove_duplicates_from_sorted_list.rs} (94%)
 rename src/{n0084_largest_rectangle_in_histogram.rs => solution/s0084_largest_rectangle_in_histogram.rs} (100%)
 rename src/{n0085_maximal_rectangle.rs => solution/s0085_maximal_rectangle.rs} (100%)
 rename src/{n0086_partition_list.rs => solution/s0086_partition_list.rs} (97%)
 rename src/{n0087_scramble_string.rs => solution/s0087_scramble_string.rs} (100%)
 rename src/{n0088_merge_sorted_array.rs => solution/s0088_merge_sorted_array.rs} (100%)
 rename src/{n0089_gray_code.rs => solution/s0089_gray_code.rs} (100%)
 rename src/{n0090_subsets_ii.rs => solution/s0090_subsets_ii.rs} (100%)
 rename src/{n0091_decode_ways.rs => solution/s0091_decode_ways.rs} (100%)
 rename src/{n0092_reverse_linked_list_ii.rs => solution/s0092_reverse_linked_list_ii.rs} (94%)
 rename src/{n0093_restore_ip_addresses.rs => solution/s0093_restore_ip_addresses.rs} (100%)
 rename src/{n0094_binary_tree_inorder_traversal.rs => solution/s0094_binary_tree_inorder_traversal.rs} (96%)
 rename src/{n0095_unique_binary_search_trees_ii.rs => solution/s0095_unique_binary_search_trees_ii.rs} (97%)
 rename src/{n0096_unique_binary_search_trees.rs => solution/s0096_unique_binary_search_trees.rs} (100%)
 rename src/{n0097_interleaving_string.rs => solution/s0097_interleaving_string.rs} (100%)
 rename src/{n0098_validate_binary_search_tree.rs => solution/s0098_validate_binary_search_tree.rs} (98%)
 rename src/{n0099_recover_binary_search_tree.rs => solution/s0099_recover_binary_search_tree.rs} (95%)
 rename src/{n0100_same_tree.rs => solution/s0100_same_tree.rs} (96%)
 rename src/{n0101_symmetric_tree.rs => solution/s0101_symmetric_tree.rs} (97%)
 rename src/{n0102_binary_tree_level_order_traversal.rs => solution/s0102_binary_tree_level_order_traversal.rs} (97%)
 rename src/{n0103_binary_tree_zigzag_level_order_traversal.rs => solution/s0103_binary_tree_zigzag_level_order_traversal.rs} (97%)
 rename src/{n0104_maximum_depth_of_binary_tree.rs => solution/s0104_maximum_depth_of_binary_tree.rs} (96%)
 rename src/{n0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs => solution/s0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs} (97%)
 rename src/{n0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs => solution/s0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs} (97%)
 rename src/{n0107_binary_tree_level_order_traversal_ii.rs => solution/s0107_binary_tree_level_order_traversal_ii.rs} (97%)
 rename src/{n0108_convert_sorted_array_to_binary_search_tree.rs => solution/s0108_convert_sorted_array_to_binary_search_tree.rs} (97%)
 rename src/{n0109_convert_sorted_list_to_binary_search_tree.rs => solution/s0109_convert_sorted_list_to_binary_search_tree.rs} (94%)
 rename src/{n0110_balanced_binary_tree.rs => solution/s0110_balanced_binary_tree.rs} (93%)
 rename src/{n0111_minimum_depth_of_binary_tree.rs => solution/s0111_minimum_depth_of_binary_tree.rs} (96%)
 rename src/{n0112_path_sum.rs => solution/s0112_path_sum.rs} (97%)
 rename src/{n0113_path_sum_ii.rs => solution/s0113_path_sum_ii.rs} (97%)
 rename src/{n0114_flatten_binary_tree_to_linked_list.rs => solution/s0114_flatten_binary_tree_to_linked_list.rs} (97%)
 rename src/{n0115_distinct_subsequences.rs => solution/s0115_distinct_subsequences.rs} (100%)
 rename src/{n0118_pascals_triangle.rs => solution/s0118_pascals_triangle.rs} (100%)
 rename src/{n0119_pascals_triangle_ii.rs => solution/s0119_pascals_triangle_ii.rs} (100%)
 rename src/{n0120_triangle.rs => solution/s0120_triangle.rs} (100%)
 rename src/{n0121_best_time_to_buy_and_sell_stock.rs => solution/s0121_best_time_to_buy_and_sell_stock.rs} (100%)
 rename src/{n0122_best_time_to_buy_and_sell_stock_ii.rs => solution/s0122_best_time_to_buy_and_sell_stock_ii.rs} (100%)
 rename src/{n0123_best_time_to_buy_and_sell_stock_iii.rs => solution/s0123_best_time_to_buy_and_sell_stock_iii.rs} (100%)
 rename src/{n0124_binary_tree_maximum_path_sum.rs => solution/s0124_binary_tree_maximum_path_sum.rs} (98%)
 rename src/{n0125_valid_palindrome.rs => solution/s0125_valid_palindrome.rs} (100%)
 rename src/{n0126_word_ladder_ii.rs => solution/s0126_word_ladder_ii.rs} (100%)
 rename src/{n0127_word_ladder.rs => solution/s0127_word_ladder.rs} (100%)
 rename src/{n0128_longest_consecutive_sequence.rs => solution/s0128_longest_consecutive_sequence.rs} (100%)
 rename src/{n0129_sum_root_to_leaf_numbers.rs => solution/s0129_sum_root_to_leaf_numbers.rs} (97%)
 rename src/{n0130_surrounded_regions.rs => solution/s0130_surrounded_regions.rs} (100%)
 rename src/{n0131_palindrome_partitioning.rs => solution/s0131_palindrome_partitioning.rs} (100%)
 rename src/{n0132_palindrome_partitioning_ii.rs => solution/s0132_palindrome_partitioning_ii.rs} (100%)
 rename src/{n0134_gas_station.rs => solution/s0134_gas_station.rs} (100%)
 rename src/{n0135_candy.rs => solution/s0135_candy.rs} (100%)
 rename src/{n0136_single_number.rs => solution/s0136_single_number.rs} (100%)
 rename src/{n0137_single_number_ii.rs => solution/s0137_single_number_ii.rs} (100%)
 rename src/{n0139_word_break.rs => solution/s0139_word_break.rs} (100%)
 rename src/{n0140_word_break_ii.rs => solution/s0140_word_break_ii.rs} (100%)
 rename src/{n0143_reorder_list.rs => solution/s0143_reorder_list.rs} (93%)
 rename src/{n0144_binary_tree_preorder_traversal.rs => solution/s0144_binary_tree_preorder_traversal.rs} (96%)
 rename src/{n0145_binary_tree_postorder_traversal.rs => solution/s0145_binary_tree_postorder_traversal.rs} (96%)
 rename src/{n0146_lru_cache.rs => solution/s0146_lru_cache.rs} (100%)
 rename src/{n0147_insertion_sort_list.rs => solution/s0147_insertion_sort_list.rs} (96%)
 rename src/{n0148_sort_list.rs => solution/s0148_sort_list.rs} (98%)
 rename src/{n0149_max_points_on_a_line.rs => solution/s0149_max_points_on_a_line.rs} (95%)
 rename src/{n0150_evaluate_reverse_polish_notation.rs => solution/s0150_evaluate_reverse_polish_notation.rs} (100%)
 rename src/{n0151_reverse_words_in_a_string.rs => solution/s0151_reverse_words_in_a_string.rs} (100%)
 rename src/{n0152_maximum_product_subarray.rs => solution/s0152_maximum_product_subarray.rs} (100%)
 rename src/{n0153_find_minimum_in_rotated_sorted_array.rs => solution/s0153_find_minimum_in_rotated_sorted_array.rs} (100%)
 rename src/{n0154_find_minimum_in_rotated_sorted_array_ii.rs => solution/s0154_find_minimum_in_rotated_sorted_array_ii.rs} (100%)
 rename src/{n0155_min_stack.rs => solution/s0155_min_stack.rs} (100%)
 rename src/{n0162_find_peak_element.rs => solution/s0162_find_peak_element.rs} (100%)
 rename src/{n0164_maximum_gap.rs => solution/s0164_maximum_gap.rs} (100%)
 rename src/{n0165_compare_version_numbers.rs => solution/s0165_compare_version_numbers.rs} (100%)
 rename src/{n0166_fraction_to_recurring_decimal.rs => solution/s0166_fraction_to_recurring_decimal.rs} (100%)
 rename src/{n0167_two_sum_ii_input_array_is_sorted.rs => solution/s0167_two_sum_ii_input_array_is_sorted.rs} (100%)
 rename src/{n0168_excel_sheet_column_title.rs => solution/s0168_excel_sheet_column_title.rs} (100%)
 rename src/{n0169_majority_element.rs => solution/s0169_majority_element.rs} (100%)
 rename src/{n0171_excel_sheet_column_number.rs => solution/s0171_excel_sheet_column_number.rs} (100%)
 rename src/{n0172_factorial_trailing_zeroes.rs => solution/s0172_factorial_trailing_zeroes.rs} (100%)
 rename src/{n0173_binary_search_tree_iterator.rs => solution/s0173_binary_search_tree_iterator.rs} (94%)
 rename src/{n0174_dungeon_game.rs => solution/s0174_dungeon_game.rs} (100%)
 rename src/{n0179_largest_number.rs => solution/s0179_largest_number.rs} (100%)
 rename src/{n0187_repeated_dna_sequences.rs => solution/s0187_repeated_dna_sequences.rs} (100%)
 rename src/{n0188_best_time_to_buy_and_sell_stock_iv.rs => solution/s0188_best_time_to_buy_and_sell_stock_iv.rs} (100%)
 rename src/{n0189_rotate_array.rs => solution/s0189_rotate_array.rs} (100%)
 rename src/{n0198_house_robber.rs => solution/s0198_house_robber.rs} (100%)
 rename src/{n0199_binary_tree_right_side_view.rs => solution/s0199_binary_tree_right_side_view.rs} (97%)
 rename src/{n0200_number_of_islands.rs => solution/s0200_number_of_islands.rs} (100%)
 rename src/{n0201_bitwise_and_of_numbers_range.rs => solution/s0201_bitwise_and_of_numbers_range.rs} (100%)
 rename src/{n0202_happy_number.rs => solution/s0202_happy_number.rs} (100%)
 rename src/{n0203_remove_linked_list_elements.rs => solution/s0203_remove_linked_list_elements.rs} (95%)
 rename src/{n0204_count_primes.rs => solution/s0204_count_primes.rs} (100%)
 rename src/{n0205_isomorphic_strings.rs => solution/s0205_isomorphic_strings.rs} (100%)
 rename src/{n0206_reverse_linked_list.rs => solution/s0206_reverse_linked_list.rs} (94%)
 rename src/{n0207_course_schedule.rs => solution/s0207_course_schedule.rs} (100%)
 rename src/{n0208_implement_trie_prefix_tree.rs => solution/s0208_implement_trie_prefix_tree.rs} (100%)
 rename src/{n0209_minimum_size_subarray_sum.rs => solution/s0209_minimum_size_subarray_sum.rs} (100%)
 rename src/{n0210_course_schedule_ii.rs => solution/s0210_course_schedule_ii.rs} (100%)
 rename src/{n0211_add_and_search_word_data_structure_design.rs => solution/s0211_add_and_search_word_data_structure_design.rs} (100%)
 rename src/{n0212_word_search_ii.rs => solution/s0212_word_search_ii.rs} (100%)
 rename src/{n0213_house_robber_ii.rs => solution/s0213_house_robber_ii.rs} (100%)
 rename src/{n0214_shortest_palindrome.rs => solution/s0214_shortest_palindrome.rs} (100%)
 rename src/{n0215_kth_largest_element_in_an_array.rs => solution/s0215_kth_largest_element_in_an_array.rs} (100%)
 rename src/{n0216_combination_sum_iii.rs => solution/s0216_combination_sum_iii.rs} (100%)
 rename src/{n0217_contains_duplicate.rs => solution/s0217_contains_duplicate.rs} (100%)
 rename src/{n0218_the_skyline_problem.rs => solution/s0218_the_skyline_problem.rs} (100%)
 rename src/{n0219_contains_duplicate_ii.rs => solution/s0219_contains_duplicate_ii.rs} (100%)
 rename src/{n0220_contains_duplicate_iii.rs => solution/s0220_contains_duplicate_iii.rs} (100%)
 rename src/{n0221_maximal_square.rs => solution/s0221_maximal_square.rs} (100%)
 rename src/{n0222_count_complete_tree_nodes.rs => solution/s0222_count_complete_tree_nodes.rs} (98%)
 rename src/{n0223_rectangle_area.rs => solution/s0223_rectangle_area.rs} (100%)
 rename src/{n0224_basic_calculator.rs => solution/s0224_basic_calculator.rs} (100%)
 rename src/{n0225_implement_stack_using_queues.rs => solution/s0225_implement_stack_using_queues.rs} (100%)
 rename src/{n0226_invert_binary_tree.rs => solution/s0226_invert_binary_tree.rs} (97%)
 rename src/{n0227_basic_calculator_ii.rs => solution/s0227_basic_calculator_ii.rs} (100%)
 rename src/{n0228_summary_ranges.rs => solution/s0228_summary_ranges.rs} (100%)
 rename src/{n0229_majority_element_ii.rs => solution/s0229_majority_element_ii.rs} (100%)
 rename src/{n0230_kth_smallest_element_in_a_bst.rs => solution/s0230_kth_smallest_element_in_a_bst.rs} (97%)
 rename src/{n0231_power_of_two.rs => solution/s0231_power_of_two.rs} (100%)
 rename src/{n0232_implement_queue_using_stacks.rs => solution/s0232_implement_queue_using_stacks.rs} (100%)
 rename src/{n0233_number_of_digit_one.rs => solution/s0233_number_of_digit_one.rs} (100%)
 rename src/{n0238_product_of_array_except_self.rs => solution/s0238_product_of_array_except_self.rs} (100%)
 rename src/{n0239_sliding_window_maximum.rs => solution/s0239_sliding_window_maximum.rs} (100%)
 rename src/{n0241_different_ways_to_add_parentheses.rs => solution/s0241_different_ways_to_add_parentheses.rs} (100%)
 rename src/{n0242_valid_anagram.rs => solution/s0242_valid_anagram.rs} (100%)
 rename src/{n0257_binary_tree_paths.rs => solution/s0257_binary_tree_paths.rs} (97%)
 rename src/{n0258_add_digits.rs => solution/s0258_add_digits.rs} (100%)
 rename src/{n0260_single_number_iii.rs => solution/s0260_single_number_iii.rs} (100%)
 rename src/{n0263_ugly_number.rs => solution/s0263_ugly_number.rs} (100%)
 rename src/{n0264_ugly_number_ii.rs => solution/s0264_ugly_number_ii.rs} (100%)
 rename src/{n0268_missing_number.rs => solution/s0268_missing_number.rs} (100%)
 rename src/{n0273_integer_to_english_words.rs => solution/s0273_integer_to_english_words.rs} (100%)
 rename src/{n0274_h_index.rs => solution/s0274_h_index.rs} (100%)
 rename src/{n0275_h_index_ii.rs => solution/s0275_h_index_ii.rs} (100%)
 rename src/{n0279_perfect_squares.rs => solution/s0279_perfect_squares.rs} (100%)
 rename src/{n0282_expression_add_operators.rs => solution/s0282_expression_add_operators.rs} (100%)
 rename src/{n0283_move_zeroes.rs => solution/s0283_move_zeroes.rs} (100%)
 rename src/{n0287_find_the_duplicate_number.rs => solution/s0287_find_the_duplicate_number.rs} (100%)
 rename src/{n0289_game_of_life.rs => solution/s0289_game_of_life.rs} (100%)
 rename src/{n0290_word_pattern.rs => solution/s0290_word_pattern.rs} (100%)
 rename src/{n0292_nim_game.rs => solution/s0292_nim_game.rs} (100%)
 rename src/{n0295_find_median_from_data_stream.rs => solution/s0295_find_median_from_data_stream.rs} (100%)
 rename src/{n0299_bulls_and_cows.rs => solution/s0299_bulls_and_cows.rs} (100%)
 rename src/{n0300_longest_increasing_subsequence.rs => solution/s0300_longest_increasing_subsequence.rs} (100%)
 rename src/{n0301_remove_invalid_parentheses.rs => solution/s0301_remove_invalid_parentheses.rs} (100%)
 rename src/{n0303_range_sum_query_immutable.rs => solution/s0303_range_sum_query_immutable.rs} (100%)
 rename src/{n0304_range_sum_query_2d_immutable.rs => solution/s0304_range_sum_query_2d_immutable.rs} (100%)
 rename src/{n0306_additive_number.rs => solution/s0306_additive_number.rs} (100%)
 rename src/{n0307_range_sum_query_mutable.rs => solution/s0307_range_sum_query_mutable.rs} (100%)
 rename src/{n0309_best_time_to_buy_and_sell_stock_with_cooldown.rs => solution/s0309_best_time_to_buy_and_sell_stock_with_cooldown.rs} (100%)
 rename src/{n0310_minimum_height_trees.rs => solution/s0310_minimum_height_trees.rs} (100%)
 rename src/{n0312_burst_balloons.rs => solution/s0312_burst_balloons.rs} (100%)
 rename src/{n0313_super_ugly_number.rs => solution/s0313_super_ugly_number.rs} (100%)
 rename src/{n0509_fibonacci_number.rs => solution/s0509_fibonacci_number.rs} (100%)
 rename src/{n0704_binary_search.rs => solution/s0704_binary_search.rs} (100%)
 rename src/{n0969_pancake_sorting.rs => solution/s0969_pancake_sorting.rs} (100%)
 rename src/{n1018_binary_prefix_divisible_by_5.rs => solution/s1018_binary_prefix_divisible_by_5.rs} (100%)
 rename src/{n1046_last_stone_weight.rs => solution/s1046_last_stone_weight.rs} (100%)

diff --git a/.gitignore b/.gitignore
index 2f7896d1..96ef862d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 target/
+.idea/
diff --git a/src/problem.rs b/src/fetcher.rs
similarity index 100%
rename from src/problem.rs
rename to src/fetcher.rs
diff --git a/src/lib.rs b/src/lib.rs
index 815c1ce0..55b0298f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,240 +1,5 @@
 #[macro_use]
 pub mod util;
 
-mod n0006_zigzag_conversion;
-mod n0238_product_of_array_except_self;
-mod n0115_distinct_subsequences;
-mod n0099_recover_binary_search_tree;
-mod n0310_minimum_height_trees;
-mod n0128_longest_consecutive_sequence;
-mod n0274_h_index;
-mod n0241_different_ways_to_add_parentheses;
-mod n0024_swap_nodes_in_pairs;
-mod n0110_balanced_binary_tree;
-mod n0093_restore_ip_addresses;
-mod n0076_minimum_window_substring;
-mod n0124_binary_tree_maximum_path_sum;
-mod n0122_best_time_to_buy_and_sell_stock_ii;
-mod n0169_majority_element;
-mod n0162_find_peak_element;
-mod n0095_unique_binary_search_trees_ii;
-mod n0155_min_stack;
-mod n0040_combination_sum_ii;
-mod n0217_contains_duplicate;
-mod n0055_jump_game;
-mod n0106_construct_binary_tree_from_inorder_and_postorder_traversal;
-mod n0145_binary_tree_postorder_traversal;
-mod n0079_word_search;
-mod n0969_pancake_sorting;
-mod n0042_trapping_rain_water;
-mod n0108_convert_sorted_array_to_binary_search_tree;
-mod n0083_remove_duplicates_from_sorted_list;
-mod n0130_surrounded_regions;
-mod n0226_invert_binary_tree;
-mod n0027_remove_element;
-mod n0188_best_time_to_buy_and_sell_stock_iv;
-mod n0204_count_primes;
-mod n0268_missing_number;
-mod n0214_shortest_palindrome;
-mod n0231_power_of_two;
-mod n0202_happy_number;
-mod n0075_sort_colors;
-mod n0066_plus_one;
-mod n0028_implement_strstr;
-mod n0290_word_pattern;
-mod n0048_rotate_image;
-mod n0089_gray_code;
-mod n0147_insertion_sort_list;
-mod n0084_largest_rectangle_in_histogram;
-mod n0011_container_with_most_water;
-mod n0009_palindrome_number;
-mod n0058_length_of_last_word;
-mod n0080_remove_duplicates_from_sorted_array_ii;
-mod n0030_substring_with_concatenation_of_all_words;
-mod n0060_permutation_sequence;
-mod n0071_simplify_path;
-mod n0038_count_and_say;
-mod n0144_binary_tree_preorder_traversal;
-mod n0279_perfect_squares;
-mod n0304_range_sum_query_2d_immutable;
-mod n0292_nim_game;
-mod n0264_ugly_number_ii;
-mod n0132_palindrome_partitioning_ii;
-mod n0019_remove_nth_node_from_end_of_list;
-mod n0136_single_number;
-mod n0018_4sum;
-mod n0220_contains_duplicate_iii;
-mod n0299_bulls_and_cows;
-mod n0232_implement_queue_using_stacks;
-mod n0100_same_tree;
-mod n0171_excel_sheet_column_number;
-mod n0087_scramble_string;
-mod n0704_binary_search;
-mod n0219_contains_duplicate_ii;
-mod n0086_partition_list;
-mod n0082_remove_duplicates_from_sorted_list_ii;
-mod n0228_summary_ranges;
-mod n0020_valid_parentheses;
-mod n0017_letter_combinations_of_a_phone_number;
-mod n0312_burst_balloons;
-mod n0306_additive_number;
-mod n0283_move_zeroes;
-mod n1018_binary_prefix_divisible_by_5;
-mod n0201_bitwise_and_of_numbers_range;
-mod n0109_convert_sorted_list_to_binary_search_tree;
-mod n0101_symmetric_tree;
-mod n0098_validate_binary_search_tree;
-mod n0035_search_insert_position;
-mod n0050_powx_n;
-mod n0198_house_robber;
-mod n0004_median_of_two_sorted_arrays;
-mod n0221_maximal_square;
-mod n0047_permutations_ii;
-mod n0172_factorial_trailing_zeroes;
-mod n0054_spiral_matrix;
-mod n0053_maximum_subarray;
-mod n1046_last_stone_weight;
-mod n0146_lru_cache;
-mod n0126_word_ladder_ii;
-mod n0242_valid_anagram;
-mod n0112_path_sum;
-mod n0023_merge_k_sorted_lists;
-mod n0230_kth_smallest_element_in_a_bst;
-mod n0104_maximum_depth_of_binary_tree;
-mod n0258_add_digits;
-mod n0187_repeated_dna_sequences;
-mod n0025_reverse_nodes_in_k_group;
-mod n0039_combination_sum;
-mod n0107_binary_tree_level_order_traversal_ii;
-mod n0091_decode_ways;
-mod n0056_merge_intervals;
-mod n0065_valid_number;
-mod n0016_3sum_closest;
-mod n0096_unique_binary_search_trees;
-mod n0072_edit_distance;
-mod n0044_wildcard_matching;
-mod n0239_sliding_window_maximum;
-mod n0174_dungeon_game;
-mod n0073_set_matrix_zeroes;
-mod n0078_subsets;
-mod n0037_sudoku_solver;
-mod n0033_search_in_rotated_sorted_array;
-mod n0002_add_two_numbers;
-mod n0313_super_ugly_number;
-mod n0068_text_justification;
-mod n0064_minimum_path_sum;
-mod n0218_the_skyline_problem;
-mod n0125_valid_palindrome;
-mod n0210_course_schedule_ii;
-mod n0143_reorder_list;
-mod n0164_maximum_gap;
-mod n0097_interleaving_string;
-mod n0105_construct_binary_tree_from_preorder_and_inorder_traversal;
-mod n0167_two_sum_ii_input_array_is_sorted;
-mod n0034_find_first_and_last_position_of_element_in_sorted_array;
-mod n0094_binary_tree_inorder_traversal;
-mod n0052_n_queens_ii;
-mod n0121_best_time_to_buy_and_sell_stock;
-mod n0273_integer_to_english_words;
-mod n0225_implement_stack_using_queues;
-mod n0046_permutations;
-mod n0085_maximal_rectangle;
-mod n0135_candy;
-mod n0113_path_sum_ii;
-mod n0029_divide_two_integers;
-mod n0260_single_number_iii;
-mod n0140_word_break_ii;
-mod n0149_max_points_on_a_line;
-mod n0213_house_robber_ii;
-mod n0222_count_complete_tree_nodes;
-mod n0134_gas_station;
-mod n0057_insert_interval;
-mod n0173_binary_search_tree_iterator;
-mod n0077_combinations;
-mod n0005_longest_palindromic_substring;
-mod n0041_first_missing_positive;
-mod n0026_remove_duplicates_from_sorted_array;
-mod n0166_fraction_to_recurring_decimal;
-mod n0119_pascals_triangle_ii;
-mod n0012_integer_to_roman;
-mod n0223_rectangle_area;
-mod n0229_majority_element_ii;
-mod n0061_rotate_list;
-mod n0123_best_time_to_buy_and_sell_stock_iii;
-mod n0301_remove_invalid_parentheses;
-mod n0067_add_binary;
-mod n0049_group_anagrams;
-mod n0189_rotate_array;
-mod n0001_two_sum;
-mod n0275_h_index_ii;
-mod n0103_binary_tree_zigzag_level_order_traversal;
-mod n0137_single_number_ii;
-mod n0208_implement_trie_prefix_tree;
-mod n0300_longest_increasing_subsequence;
-mod n0118_pascals_triangle;
-mod n0010_regular_expression_matching;
-mod n0013_roman_to_integer;
-mod n0209_minimum_size_subarray_sum;
-mod n0227_basic_calculator_ii;
-mod n0022_generate_parentheses;
-mod n0008_string_to_integer_atoi;
-mod n0152_maximum_product_subarray;
-mod n0014_longest_common_prefix;
-mod n0070_climbing_stairs;
-mod n0233_number_of_digit_one;
-mod n0154_find_minimum_in_rotated_sorted_array_ii;
-mod n0127_word_ladder;
-mod n0207_course_schedule;
-mod n0263_ugly_number;
-mod n0295_find_median_from_data_stream;
-mod n0148_sort_list;
-mod n0257_binary_tree_paths;
-mod n0120_triangle;
-mod n0309_best_time_to_buy_and_sell_stock_with_cooldown;
-mod n0074_search_a_2d_matrix;
-mod n0215_kth_largest_element_in_an_array;
-mod n0203_remove_linked_list_elements;
-mod n0081_search_in_rotated_sorted_array_ii;
-mod n0059_spiral_matrix_ii;
-mod n0151_reverse_words_in_a_string;
-mod n0205_isomorphic_strings;
-mod n0179_largest_number;
-mod n0168_excel_sheet_column_title;
-mod n0007_reverse_integer;
-mod n0032_longest_valid_parentheses;
-mod n0165_compare_version_numbers;
-mod n0031_next_permutation;
-mod n0088_merge_sorted_array;
-mod n0509_fibonacci_number;
-mod n0036_valid_sudoku;
-mod n0069_sqrtx;
-mod n0211_add_and_search_word_data_structure_design;
-mod n0114_flatten_binary_tree_to_linked_list;
-mod n0224_basic_calculator;
-mod n0045_jump_game_ii;
-mod n0051_n_queens;
-mod n0212_word_search_ii;
-mod n0287_find_the_duplicate_number;
-mod n0153_find_minimum_in_rotated_sorted_array;
-mod n0289_game_of_life;
-mod n0200_number_of_islands;
-mod n0015_3sum;
-mod n0216_combination_sum_iii;
-mod n0043_multiply_strings;
-mod n0090_subsets_ii;
-mod n0003_longest_substring;
-mod n0139_word_break;
-mod n0150_evaluate_reverse_polish_notation;
-mod n0063_unique_paths_ii;
-mod n0062_unique_paths;
-mod n0199_binary_tree_right_side_view;
-mod n0282_expression_add_operators;
-mod n0021_merge_two_sorted_lists;
-mod n0129_sum_root_to_leaf_numbers;
-mod n0206_reverse_linked_list;
-mod n0131_palindrome_partitioning;
-mod n0307_range_sum_query_mutable;
-mod n0111_minimum_depth_of_binary_tree;
-mod n0092_reverse_linked_list_ii;
-mod n0303_range_sum_query_immutable;
-mod n0102_binary_tree_level_order_traversal;
+pub mod solution;
+pub mod problem;
diff --git a/src/main.rs b/src/main.rs
index 967c5f85..e25be217 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,7 +3,7 @@ extern crate serde_derive;
 #[macro_use]
 extern crate serde_json;
 
-mod problem;
+mod fetcher;
 
 use std::env;
 use std::fs;
@@ -45,7 +45,7 @@ fn main() {
             }
         }
 
-        let problem = problem::get_problem(id).unwrap_or_else(|| {
+        let problem = fetcher::get_problem(id).unwrap_or_else(|| {
             panic!(
                 "Error: failed to get problem #{} \
                  (The problem may be paid-only or may not be exist).",
@@ -61,11 +61,11 @@ fn main() {
         let code = code.unwrap();
 
         let file_name = format!(
-            "n{:04}_{}",
+            "p{:04}_{}",
             problem.question_id,
             problem.title_slug.replace("-", "_")
         );
-        let file_path = Path::new("./src").join(format!("{}.rs", file_name));
+        let file_path = Path::new("./src/problem").join(format!("{}.rs", file_name));
         if file_path.exists() {
             panic!("problem already initialized");
         }
@@ -91,7 +91,7 @@ fn main() {
         let mut lib_file = fs::OpenOptions::new()
             .write(true)
             .append(true)
-            .open("./src/lib.rs")
+            .open("./src/problem/mod.rs")
             .unwrap();
         writeln!(lib_file, "mod {};", file_name);
         break;
@@ -136,13 +136,13 @@ fn parse_extra_use(code: &str) -> String {
     let mut extra_use_line = String::new();
     // a linked-list problem
     if code.contains("pub struct ListNode") {
-        extra_use_line.push_str("\nuse super::util::linked_list::{ListNode, to_list};")
+        extra_use_line.push_str("\nuse crate::util::linked_list::{ListNode, to_list};")
     }
     if code.contains("pub struct TreeNode") {
-        extra_use_line.push_str("\nuse super::util::tree::{TreeNode, to_tree};")
+        extra_use_line.push_str("\nuse crate::util::tree::{TreeNode, to_tree};")
     }
     if code.contains("pub struct Point") {
-        extra_use_line.push_str("\nuse super::util::point::Point;")
+        extra_use_line.push_str("\nuse crate::util::point::Point;")
     }
     extra_use_line
 }
diff --git a/src/problem/mod.rs b/src/problem/mod.rs
new file mode 100644
index 00000000..e69de29b
diff --git a/src/solution/mod.rs b/src/solution/mod.rs
new file mode 100644
index 00000000..3b079b74
--- /dev/null
+++ b/src/solution/mod.rs
@@ -0,0 +1,237 @@
+mod s0006_zigzag_conversion;
+mod s0238_product_of_array_except_self;
+mod s0115_distinct_subsequences;
+mod s0099_recover_binary_search_tree;
+mod s0310_minimum_height_trees;
+mod s0128_longest_consecutive_sequence;
+mod s0274_h_index;
+mod s0241_different_ways_to_add_parentheses;
+mod s0024_swap_nodes_in_pairs;
+mod s0110_balanced_binary_tree;
+mod s0093_restore_ip_addresses;
+mod s0076_minimum_window_substring;
+mod s0124_binary_tree_maximum_path_sum;
+mod s0122_best_time_to_buy_and_sell_stock_ii;
+mod s0169_majority_element;
+mod s0162_find_peak_element;
+mod s0095_unique_binary_search_trees_ii;
+mod s0155_min_stack;
+mod s0040_combination_sum_ii;
+mod s0217_contains_duplicate;
+mod s0055_jump_game;
+mod s0106_construct_binary_tree_from_inorder_and_postorder_traversal;
+mod s0145_binary_tree_postorder_traversal;
+mod s0079_word_search;
+mod s0969_pancake_sorting;
+mod s0042_trapping_rain_water;
+mod s0108_convert_sorted_array_to_binary_search_tree;
+mod s0083_remove_duplicates_from_sorted_list;
+mod s0130_surrounded_regions;
+mod s0226_invert_binary_tree;
+mod s0027_remove_element;
+mod s0188_best_time_to_buy_and_sell_stock_iv;
+mod s0204_count_primes;
+mod s0268_missing_number;
+mod s0214_shortest_palindrome;
+mod s0231_power_of_two;
+mod s0202_happy_number;
+mod s0075_sort_colors;
+mod s0066_plus_one;
+mod s0028_implement_strstr;
+mod s0290_word_pattern;
+mod s0048_rotate_image;
+mod s0089_gray_code;
+mod s0147_insertion_sort_list;
+mod s0084_largest_rectangle_in_histogram;
+mod s0011_container_with_most_water;
+mod s0009_palindrome_number;
+mod s0058_length_of_last_word;
+mod s0080_remove_duplicates_from_sorted_array_ii;
+mod s0030_substring_with_concatenation_of_all_words;
+mod s0060_permutation_sequence;
+mod s0071_simplify_path;
+mod s0038_count_and_say;
+mod s0144_binary_tree_preorder_traversal;
+mod s0279_perfect_squares;
+mod s0304_range_sum_query_2d_immutable;
+mod s0292_nim_game;
+mod s0264_ugly_number_ii;
+mod s0132_palindrome_partitioning_ii;
+mod s0019_remove_nth_node_from_end_of_list;
+mod s0136_single_number;
+mod s0018_4sum;
+mod s0220_contains_duplicate_iii;
+mod s0299_bulls_and_cows;
+mod s0232_implement_queue_using_stacks;
+mod s0100_same_tree;
+mod s0171_excel_sheet_column_number;
+mod s0087_scramble_string;
+mod s0704_binary_search;
+mod s0219_contains_duplicate_ii;
+mod s0086_partition_list;
+mod s0082_remove_duplicates_from_sorted_list_ii;
+mod s0228_summary_ranges;
+mod s0020_valid_parentheses;
+mod s0017_letter_combinations_of_a_phone_number;
+mod s0312_burst_balloons;
+mod s0306_additive_number;
+mod s0283_move_zeroes;
+mod s1018_binary_prefix_divisible_by_5;
+mod s0201_bitwise_and_of_numbers_range;
+mod s0109_convert_sorted_list_to_binary_search_tree;
+mod s0101_symmetric_tree;
+mod s0098_validate_binary_search_tree;
+mod s0035_search_insert_position;
+mod s0050_powx_n;
+mod s0198_house_robber;
+mod s0004_median_of_two_sorted_arrays;
+mod s0221_maximal_square;
+mod s0047_permutations_ii;
+mod s0172_factorial_trailing_zeroes;
+mod s0054_spiral_matrix;
+mod s0053_maximum_subarray;
+mod s1046_last_stone_weight;
+mod s0146_lru_cache;
+mod s0126_word_ladder_ii;
+mod s0242_valid_anagram;
+mod s0112_path_sum;
+mod s0023_merge_k_sorted_lists;
+mod s0230_kth_smallest_element_in_a_bst;
+mod s0104_maximum_depth_of_binary_tree;
+mod s0258_add_digits;
+mod s0187_repeated_dna_sequences;
+mod s0025_reverse_nodes_in_k_group;
+mod s0039_combination_sum;
+mod s0107_binary_tree_level_order_traversal_ii;
+mod s0091_decode_ways;
+mod s0056_merge_intervals;
+mod s0065_valid_number;
+mod s0016_3sum_closest;
+mod s0096_unique_binary_search_trees;
+mod s0072_edit_distance;
+mod s0044_wildcard_matching;
+mod s0239_sliding_window_maximum;
+mod s0174_dungeon_game;
+mod s0073_set_matrix_zeroes;
+mod s0078_subsets;
+mod s0037_sudoku_solver;
+mod s0033_search_in_rotated_sorted_array;
+mod s0002_add_two_numbers;
+mod s0313_super_ugly_number;
+mod s0068_text_justification;
+mod s0064_minimum_path_sum;
+mod s0218_the_skyline_problem;
+mod s0125_valid_palindrome;
+mod s0210_course_schedule_ii;
+mod s0143_reorder_list;
+mod s0164_maximum_gap;
+mod s0097_interleaving_string;
+mod s0105_construct_binary_tree_from_preorder_and_inorder_traversal;
+mod s0167_two_sum_ii_input_array_is_sorted;
+mod s0034_find_first_and_last_position_of_element_in_sorted_array;
+mod s0094_binary_tree_inorder_traversal;
+mod s0052_n_queens_ii;
+mod s0121_best_time_to_buy_and_sell_stock;
+mod s0273_integer_to_english_words;
+mod s0225_implement_stack_using_queues;
+mod s0046_permutations;
+mod s0085_maximal_rectangle;
+mod s0135_candy;
+mod s0113_path_sum_ii;
+mod s0029_divide_two_integers;
+mod s0260_single_number_iii;
+mod s0140_word_break_ii;
+mod s0149_max_points_on_a_line;
+mod s0213_house_robber_ii;
+mod s0222_count_complete_tree_nodes;
+mod s0134_gas_station;
+mod s0057_insert_interval;
+mod s0173_binary_search_tree_iterator;
+mod s0077_combinations;
+mod s0005_longest_palindromic_substring;
+mod s0041_first_missing_positive;
+mod s0026_remove_duplicates_from_sorted_array;
+mod s0166_fraction_to_recurring_decimal;
+mod s0119_pascals_triangle_ii;
+mod s0012_integer_to_roman;
+mod s0223_rectangle_area;
+mod s0229_majority_element_ii;
+mod s0061_rotate_list;
+mod s0123_best_time_to_buy_and_sell_stock_iii;
+mod s0301_remove_invalid_parentheses;
+mod s0067_add_binary;
+mod s0049_group_anagrams;
+mod s0189_rotate_array;
+mod s0001_two_sum;
+mod s0275_h_index_ii;
+mod s0103_binary_tree_zigzag_level_order_traversal;
+mod s0137_single_number_ii;
+mod s0208_implement_trie_prefix_tree;
+mod s0300_longest_increasing_subsequence;
+mod s0118_pascals_triangle;
+mod s0010_regular_expression_matching;
+mod s0013_roman_to_integer;
+mod s0209_minimum_size_subarray_sum;
+mod s0227_basic_calculator_ii;
+mod s0022_generate_parentheses;
+mod s0008_string_to_integer_atoi;
+mod s0152_maximum_product_subarray;
+mod s0014_longest_common_prefix;
+mod s0070_climbing_stairs;
+mod s0233_number_of_digit_one;
+mod s0154_find_minimum_in_rotated_sorted_array_ii;
+mod s0127_word_ladder;
+mod s0207_course_schedule;
+mod s0263_ugly_number;
+mod s0295_find_median_from_data_stream;
+mod s0148_sort_list;
+mod s0257_binary_tree_paths;
+mod s0120_triangle;
+mod s0309_best_time_to_buy_and_sell_stock_with_cooldown;
+mod s0074_search_a_2d_matrix;
+mod s0215_kth_largest_element_in_an_array;
+mod s0203_remove_linked_list_elements;
+mod s0081_search_in_rotated_sorted_array_ii;
+mod s0059_spiral_matrix_ii;
+mod s0151_reverse_words_in_a_string;
+mod s0205_isomorphic_strings;
+mod s0179_largest_number;
+mod s0168_excel_sheet_column_title;
+mod s0007_reverse_integer;
+mod s0032_longest_valid_parentheses;
+mod s0165_compare_version_numbers;
+mod s0031_next_permutation;
+mod s0088_merge_sorted_array;
+mod s0509_fibonacci_number;
+mod s0036_valid_sudoku;
+mod s0069_sqrtx;
+mod s0211_add_and_search_word_data_structure_design;
+mod s0114_flatten_binary_tree_to_linked_list;
+mod s0224_basic_calculator;
+mod s0045_jump_game_ii;
+mod s0051_n_queens;
+mod s0212_word_search_ii;
+mod s0287_find_the_duplicate_number;
+mod s0153_find_minimum_in_rotated_sorted_array;
+mod s0289_game_of_life;
+mod s0200_number_of_islands;
+mod s0015_3sum;
+mod s0216_combination_sum_iii;
+mod s0043_multiply_strings;
+mod s0090_subsets_ii;
+mod s0003_longest_substring;
+mod s0139_word_break;
+mod s0150_evaluate_reverse_polish_notation;
+mod s0063_unique_paths_ii;
+mod s0062_unique_paths;
+mod s0199_binary_tree_right_side_view;
+mod s0282_expression_add_operators;
+mod s0021_merge_two_sorted_lists;
+mod s0129_sum_root_to_leaf_numbers;
+mod s0206_reverse_linked_list;
+mod s0131_palindrome_partitioning;
+mod s0307_range_sum_query_mutable;
+mod s0111_minimum_depth_of_binary_tree;
+mod s0092_reverse_linked_list_ii;
+mod s0303_range_sum_query_immutable;
+mod s0102_binary_tree_level_order_traversal;
diff --git a/src/n0001_two_sum.rs b/src/solution/s0001_two_sum.rs
similarity index 100%
rename from src/n0001_two_sum.rs
rename to src/solution/s0001_two_sum.rs
diff --git a/src/n0002_add_two_numbers.rs b/src/solution/s0002_add_two_numbers.rs
similarity index 98%
rename from src/n0002_add_two_numbers.rs
rename to src/solution/s0002_add_two_numbers.rs
index b7b21b01..5612c3d4 100644
--- a/src/n0002_add_two_numbers.rs
+++ b/src/solution/s0002_add_two_numbers.rs
@@ -17,7 +17,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0003_longest_substring.rs b/src/solution/s0003_longest_substring.rs
similarity index 100%
rename from src/n0003_longest_substring.rs
rename to src/solution/s0003_longest_substring.rs
diff --git a/src/n0004_median_of_two_sorted_arrays.rs b/src/solution/s0004_median_of_two_sorted_arrays.rs
similarity index 100%
rename from src/n0004_median_of_two_sorted_arrays.rs
rename to src/solution/s0004_median_of_two_sorted_arrays.rs
diff --git a/src/n0005_longest_palindromic_substring.rs b/src/solution/s0005_longest_palindromic_substring.rs
similarity index 100%
rename from src/n0005_longest_palindromic_substring.rs
rename to src/solution/s0005_longest_palindromic_substring.rs
diff --git a/src/n0006_zigzag_conversion.rs b/src/solution/s0006_zigzag_conversion.rs
similarity index 100%
rename from src/n0006_zigzag_conversion.rs
rename to src/solution/s0006_zigzag_conversion.rs
diff --git a/src/n0007_reverse_integer.rs b/src/solution/s0007_reverse_integer.rs
similarity index 100%
rename from src/n0007_reverse_integer.rs
rename to src/solution/s0007_reverse_integer.rs
diff --git a/src/n0008_string_to_integer_atoi.rs b/src/solution/s0008_string_to_integer_atoi.rs
similarity index 100%
rename from src/n0008_string_to_integer_atoi.rs
rename to src/solution/s0008_string_to_integer_atoi.rs
diff --git a/src/n0009_palindrome_number.rs b/src/solution/s0009_palindrome_number.rs
similarity index 100%
rename from src/n0009_palindrome_number.rs
rename to src/solution/s0009_palindrome_number.rs
diff --git a/src/n0010_regular_expression_matching.rs b/src/solution/s0010_regular_expression_matching.rs
similarity index 100%
rename from src/n0010_regular_expression_matching.rs
rename to src/solution/s0010_regular_expression_matching.rs
diff --git a/src/n0011_container_with_most_water.rs b/src/solution/s0011_container_with_most_water.rs
similarity index 100%
rename from src/n0011_container_with_most_water.rs
rename to src/solution/s0011_container_with_most_water.rs
diff --git a/src/n0012_integer_to_roman.rs b/src/solution/s0012_integer_to_roman.rs
similarity index 100%
rename from src/n0012_integer_to_roman.rs
rename to src/solution/s0012_integer_to_roman.rs
diff --git a/src/n0013_roman_to_integer.rs b/src/solution/s0013_roman_to_integer.rs
similarity index 100%
rename from src/n0013_roman_to_integer.rs
rename to src/solution/s0013_roman_to_integer.rs
diff --git a/src/n0014_longest_common_prefix.rs b/src/solution/s0014_longest_common_prefix.rs
similarity index 100%
rename from src/n0014_longest_common_prefix.rs
rename to src/solution/s0014_longest_common_prefix.rs
diff --git a/src/n0015_3sum.rs b/src/solution/s0015_3sum.rs
similarity index 100%
rename from src/n0015_3sum.rs
rename to src/solution/s0015_3sum.rs
diff --git a/src/n0016_3sum_closest.rs b/src/solution/s0016_3sum_closest.rs
similarity index 100%
rename from src/n0016_3sum_closest.rs
rename to src/solution/s0016_3sum_closest.rs
diff --git a/src/n0017_letter_combinations_of_a_phone_number.rs b/src/solution/s0017_letter_combinations_of_a_phone_number.rs
similarity index 100%
rename from src/n0017_letter_combinations_of_a_phone_number.rs
rename to src/solution/s0017_letter_combinations_of_a_phone_number.rs
diff --git a/src/n0018_4sum.rs b/src/solution/s0018_4sum.rs
similarity index 100%
rename from src/n0018_4sum.rs
rename to src/solution/s0018_4sum.rs
diff --git a/src/n0019_remove_nth_node_from_end_of_list.rs b/src/solution/s0019_remove_nth_node_from_end_of_list.rs
similarity index 97%
rename from src/n0019_remove_nth_node_from_end_of_list.rs
rename to src/solution/s0019_remove_nth_node_from_end_of_list.rs
index a1698a45..b3dac826 100644
--- a/src/n0019_remove_nth_node_from_end_of_list.rs
+++ b/src/solution/s0019_remove_nth_node_from_end_of_list.rs
@@ -21,7 +21,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0020_valid_parentheses.rs b/src/solution/s0020_valid_parentheses.rs
similarity index 100%
rename from src/n0020_valid_parentheses.rs
rename to src/solution/s0020_valid_parentheses.rs
diff --git a/src/n0021_merge_two_sorted_lists.rs b/src/solution/s0021_merge_two_sorted_lists.rs
similarity index 97%
rename from src/n0021_merge_two_sorted_lists.rs
rename to src/solution/s0021_merge_two_sorted_lists.rs
index 5a25adf7..c496d8e0 100644
--- a/src/n0021_merge_two_sorted_lists.rs
+++ b/src/solution/s0021_merge_two_sorted_lists.rs
@@ -11,7 +11,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0022_generate_parentheses.rs b/src/solution/s0022_generate_parentheses.rs
similarity index 100%
rename from src/n0022_generate_parentheses.rs
rename to src/solution/s0022_generate_parentheses.rs
diff --git a/src/n0023_merge_k_sorted_lists.rs b/src/solution/s0023_merge_k_sorted_lists.rs
similarity index 97%
rename from src/n0023_merge_k_sorted_lists.rs
rename to src/solution/s0023_merge_k_sorted_lists.rs
index 74b95045..c213eb7d 100644
--- a/src/n0023_merge_k_sorted_lists.rs
+++ b/src/solution/s0023_merge_k_sorted_lists.rs
@@ -17,7 +17,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 use std::cmp::Ordering;
diff --git a/src/n0024_swap_nodes_in_pairs.rs b/src/solution/s0024_swap_nodes_in_pairs.rs
similarity index 97%
rename from src/n0024_swap_nodes_in_pairs.rs
rename to src/solution/s0024_swap_nodes_in_pairs.rs
index 41e3c6c4..104d6b9e 100644
--- a/src/n0024_swap_nodes_in_pairs.rs
+++ b/src/solution/s0024_swap_nodes_in_pairs.rs
@@ -17,7 +17,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0025_reverse_nodes_in_k_group.rs b/src/solution/s0025_reverse_nodes_in_k_group.rs
similarity index 98%
rename from src/n0025_reverse_nodes_in_k_group.rs
rename to src/solution/s0025_reverse_nodes_in_k_group.rs
index aac987f7..3beb5528 100644
--- a/src/n0025_reverse_nodes_in_k_group.rs
+++ b/src/solution/s0025_reverse_nodes_in_k_group.rs
@@ -25,7 +25,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0026_remove_duplicates_from_sorted_array.rs b/src/solution/s0026_remove_duplicates_from_sorted_array.rs
similarity index 100%
rename from src/n0026_remove_duplicates_from_sorted_array.rs
rename to src/solution/s0026_remove_duplicates_from_sorted_array.rs
diff --git a/src/n0027_remove_element.rs b/src/solution/s0027_remove_element.rs
similarity index 100%
rename from src/n0027_remove_element.rs
rename to src/solution/s0027_remove_element.rs
diff --git a/src/n0028_implement_strstr.rs b/src/solution/s0028_implement_strstr.rs
similarity index 100%
rename from src/n0028_implement_strstr.rs
rename to src/solution/s0028_implement_strstr.rs
diff --git a/src/n0029_divide_two_integers.rs b/src/solution/s0029_divide_two_integers.rs
similarity index 100%
rename from src/n0029_divide_two_integers.rs
rename to src/solution/s0029_divide_two_integers.rs
diff --git a/src/n0030_substring_with_concatenation_of_all_words.rs b/src/solution/s0030_substring_with_concatenation_of_all_words.rs
similarity index 100%
rename from src/n0030_substring_with_concatenation_of_all_words.rs
rename to src/solution/s0030_substring_with_concatenation_of_all_words.rs
diff --git a/src/n0031_next_permutation.rs b/src/solution/s0031_next_permutation.rs
similarity index 100%
rename from src/n0031_next_permutation.rs
rename to src/solution/s0031_next_permutation.rs
diff --git a/src/n0032_longest_valid_parentheses.rs b/src/solution/s0032_longest_valid_parentheses.rs
similarity index 100%
rename from src/n0032_longest_valid_parentheses.rs
rename to src/solution/s0032_longest_valid_parentheses.rs
diff --git a/src/n0033_search_in_rotated_sorted_array.rs b/src/solution/s0033_search_in_rotated_sorted_array.rs
similarity index 100%
rename from src/n0033_search_in_rotated_sorted_array.rs
rename to src/solution/s0033_search_in_rotated_sorted_array.rs
diff --git a/src/n0034_find_first_and_last_position_of_element_in_sorted_array.rs b/src/solution/s0034_find_first_and_last_position_of_element_in_sorted_array.rs
similarity index 100%
rename from src/n0034_find_first_and_last_position_of_element_in_sorted_array.rs
rename to src/solution/s0034_find_first_and_last_position_of_element_in_sorted_array.rs
diff --git a/src/n0035_search_insert_position.rs b/src/solution/s0035_search_insert_position.rs
similarity index 100%
rename from src/n0035_search_insert_position.rs
rename to src/solution/s0035_search_insert_position.rs
diff --git a/src/n0036_valid_sudoku.rs b/src/solution/s0036_valid_sudoku.rs
similarity index 100%
rename from src/n0036_valid_sudoku.rs
rename to src/solution/s0036_valid_sudoku.rs
diff --git a/src/n0037_sudoku_solver.rs b/src/solution/s0037_sudoku_solver.rs
similarity index 100%
rename from src/n0037_sudoku_solver.rs
rename to src/solution/s0037_sudoku_solver.rs
diff --git a/src/n0038_count_and_say.rs b/src/solution/s0038_count_and_say.rs
similarity index 100%
rename from src/n0038_count_and_say.rs
rename to src/solution/s0038_count_and_say.rs
diff --git a/src/n0039_combination_sum.rs b/src/solution/s0039_combination_sum.rs
similarity index 100%
rename from src/n0039_combination_sum.rs
rename to src/solution/s0039_combination_sum.rs
diff --git a/src/n0040_combination_sum_ii.rs b/src/solution/s0040_combination_sum_ii.rs
similarity index 100%
rename from src/n0040_combination_sum_ii.rs
rename to src/solution/s0040_combination_sum_ii.rs
diff --git a/src/n0041_first_missing_positive.rs b/src/solution/s0041_first_missing_positive.rs
similarity index 100%
rename from src/n0041_first_missing_positive.rs
rename to src/solution/s0041_first_missing_positive.rs
diff --git a/src/n0042_trapping_rain_water.rs b/src/solution/s0042_trapping_rain_water.rs
similarity index 100%
rename from src/n0042_trapping_rain_water.rs
rename to src/solution/s0042_trapping_rain_water.rs
diff --git a/src/n0043_multiply_strings.rs b/src/solution/s0043_multiply_strings.rs
similarity index 100%
rename from src/n0043_multiply_strings.rs
rename to src/solution/s0043_multiply_strings.rs
diff --git a/src/n0044_wildcard_matching.rs b/src/solution/s0044_wildcard_matching.rs
similarity index 100%
rename from src/n0044_wildcard_matching.rs
rename to src/solution/s0044_wildcard_matching.rs
diff --git a/src/n0045_jump_game_ii.rs b/src/solution/s0045_jump_game_ii.rs
similarity index 100%
rename from src/n0045_jump_game_ii.rs
rename to src/solution/s0045_jump_game_ii.rs
diff --git a/src/n0046_permutations.rs b/src/solution/s0046_permutations.rs
similarity index 100%
rename from src/n0046_permutations.rs
rename to src/solution/s0046_permutations.rs
diff --git a/src/n0047_permutations_ii.rs b/src/solution/s0047_permutations_ii.rs
similarity index 100%
rename from src/n0047_permutations_ii.rs
rename to src/solution/s0047_permutations_ii.rs
diff --git a/src/n0048_rotate_image.rs b/src/solution/s0048_rotate_image.rs
similarity index 100%
rename from src/n0048_rotate_image.rs
rename to src/solution/s0048_rotate_image.rs
diff --git a/src/n0049_group_anagrams.rs b/src/solution/s0049_group_anagrams.rs
similarity index 100%
rename from src/n0049_group_anagrams.rs
rename to src/solution/s0049_group_anagrams.rs
diff --git a/src/n0050_powx_n.rs b/src/solution/s0050_powx_n.rs
similarity index 100%
rename from src/n0050_powx_n.rs
rename to src/solution/s0050_powx_n.rs
diff --git a/src/n0051_n_queens.rs b/src/solution/s0051_n_queens.rs
similarity index 100%
rename from src/n0051_n_queens.rs
rename to src/solution/s0051_n_queens.rs
diff --git a/src/n0052_n_queens_ii.rs b/src/solution/s0052_n_queens_ii.rs
similarity index 100%
rename from src/n0052_n_queens_ii.rs
rename to src/solution/s0052_n_queens_ii.rs
diff --git a/src/n0053_maximum_subarray.rs b/src/solution/s0053_maximum_subarray.rs
similarity index 100%
rename from src/n0053_maximum_subarray.rs
rename to src/solution/s0053_maximum_subarray.rs
diff --git a/src/n0054_spiral_matrix.rs b/src/solution/s0054_spiral_matrix.rs
similarity index 100%
rename from src/n0054_spiral_matrix.rs
rename to src/solution/s0054_spiral_matrix.rs
diff --git a/src/n0055_jump_game.rs b/src/solution/s0055_jump_game.rs
similarity index 100%
rename from src/n0055_jump_game.rs
rename to src/solution/s0055_jump_game.rs
diff --git a/src/n0056_merge_intervals.rs b/src/solution/s0056_merge_intervals.rs
similarity index 100%
rename from src/n0056_merge_intervals.rs
rename to src/solution/s0056_merge_intervals.rs
diff --git a/src/n0057_insert_interval.rs b/src/solution/s0057_insert_interval.rs
similarity index 100%
rename from src/n0057_insert_interval.rs
rename to src/solution/s0057_insert_interval.rs
diff --git a/src/n0058_length_of_last_word.rs b/src/solution/s0058_length_of_last_word.rs
similarity index 100%
rename from src/n0058_length_of_last_word.rs
rename to src/solution/s0058_length_of_last_word.rs
diff --git a/src/n0059_spiral_matrix_ii.rs b/src/solution/s0059_spiral_matrix_ii.rs
similarity index 100%
rename from src/n0059_spiral_matrix_ii.rs
rename to src/solution/s0059_spiral_matrix_ii.rs
diff --git a/src/n0060_permutation_sequence.rs b/src/solution/s0060_permutation_sequence.rs
similarity index 100%
rename from src/n0060_permutation_sequence.rs
rename to src/solution/s0060_permutation_sequence.rs
diff --git a/src/n0061_rotate_list.rs b/src/solution/s0061_rotate_list.rs
similarity index 94%
rename from src/n0061_rotate_list.rs
rename to src/solution/s0061_rotate_list.rs
index 08812115..b7723576 100644
--- a/src/n0061_rotate_list.rs
+++ b/src/solution/s0061_rotate_list.rs
@@ -26,7 +26,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0062_unique_paths.rs b/src/solution/s0062_unique_paths.rs
similarity index 100%
rename from src/n0062_unique_paths.rs
rename to src/solution/s0062_unique_paths.rs
diff --git a/src/n0063_unique_paths_ii.rs b/src/solution/s0063_unique_paths_ii.rs
similarity index 100%
rename from src/n0063_unique_paths_ii.rs
rename to src/solution/s0063_unique_paths_ii.rs
diff --git a/src/n0064_minimum_path_sum.rs b/src/solution/s0064_minimum_path_sum.rs
similarity index 100%
rename from src/n0064_minimum_path_sum.rs
rename to src/solution/s0064_minimum_path_sum.rs
diff --git a/src/n0065_valid_number.rs b/src/solution/s0065_valid_number.rs
similarity index 100%
rename from src/n0065_valid_number.rs
rename to src/solution/s0065_valid_number.rs
diff --git a/src/n0066_plus_one.rs b/src/solution/s0066_plus_one.rs
similarity index 100%
rename from src/n0066_plus_one.rs
rename to src/solution/s0066_plus_one.rs
diff --git a/src/n0067_add_binary.rs b/src/solution/s0067_add_binary.rs
similarity index 100%
rename from src/n0067_add_binary.rs
rename to src/solution/s0067_add_binary.rs
diff --git a/src/n0068_text_justification.rs b/src/solution/s0068_text_justification.rs
similarity index 100%
rename from src/n0068_text_justification.rs
rename to src/solution/s0068_text_justification.rs
diff --git a/src/n0069_sqrtx.rs b/src/solution/s0069_sqrtx.rs
similarity index 100%
rename from src/n0069_sqrtx.rs
rename to src/solution/s0069_sqrtx.rs
diff --git a/src/n0070_climbing_stairs.rs b/src/solution/s0070_climbing_stairs.rs
similarity index 100%
rename from src/n0070_climbing_stairs.rs
rename to src/solution/s0070_climbing_stairs.rs
diff --git a/src/n0071_simplify_path.rs b/src/solution/s0071_simplify_path.rs
similarity index 100%
rename from src/n0071_simplify_path.rs
rename to src/solution/s0071_simplify_path.rs
diff --git a/src/n0072_edit_distance.rs b/src/solution/s0072_edit_distance.rs
similarity index 100%
rename from src/n0072_edit_distance.rs
rename to src/solution/s0072_edit_distance.rs
diff --git a/src/n0073_set_matrix_zeroes.rs b/src/solution/s0073_set_matrix_zeroes.rs
similarity index 100%
rename from src/n0073_set_matrix_zeroes.rs
rename to src/solution/s0073_set_matrix_zeroes.rs
diff --git a/src/n0074_search_a_2d_matrix.rs b/src/solution/s0074_search_a_2d_matrix.rs
similarity index 100%
rename from src/n0074_search_a_2d_matrix.rs
rename to src/solution/s0074_search_a_2d_matrix.rs
diff --git a/src/n0075_sort_colors.rs b/src/solution/s0075_sort_colors.rs
similarity index 100%
rename from src/n0075_sort_colors.rs
rename to src/solution/s0075_sort_colors.rs
diff --git a/src/n0076_minimum_window_substring.rs b/src/solution/s0076_minimum_window_substring.rs
similarity index 100%
rename from src/n0076_minimum_window_substring.rs
rename to src/solution/s0076_minimum_window_substring.rs
diff --git a/src/n0077_combinations.rs b/src/solution/s0077_combinations.rs
similarity index 100%
rename from src/n0077_combinations.rs
rename to src/solution/s0077_combinations.rs
diff --git a/src/n0078_subsets.rs b/src/solution/s0078_subsets.rs
similarity index 100%
rename from src/n0078_subsets.rs
rename to src/solution/s0078_subsets.rs
diff --git a/src/n0079_word_search.rs b/src/solution/s0079_word_search.rs
similarity index 100%
rename from src/n0079_word_search.rs
rename to src/solution/s0079_word_search.rs
diff --git a/src/n0080_remove_duplicates_from_sorted_array_ii.rs b/src/solution/s0080_remove_duplicates_from_sorted_array_ii.rs
similarity index 100%
rename from src/n0080_remove_duplicates_from_sorted_array_ii.rs
rename to src/solution/s0080_remove_duplicates_from_sorted_array_ii.rs
diff --git a/src/n0081_search_in_rotated_sorted_array_ii.rs b/src/solution/s0081_search_in_rotated_sorted_array_ii.rs
similarity index 100%
rename from src/n0081_search_in_rotated_sorted_array_ii.rs
rename to src/solution/s0081_search_in_rotated_sorted_array_ii.rs
diff --git a/src/n0082_remove_duplicates_from_sorted_list_ii.rs b/src/solution/s0082_remove_duplicates_from_sorted_list_ii.rs
similarity index 94%
rename from src/n0082_remove_duplicates_from_sorted_list_ii.rs
rename to src/solution/s0082_remove_duplicates_from_sorted_list_ii.rs
index ff8c8b8b..d04b15f8 100644
--- a/src/n0082_remove_duplicates_from_sorted_list_ii.rs
+++ b/src/solution/s0082_remove_duplicates_from_sorted_list_ii.rs
@@ -19,7 +19,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0083_remove_duplicates_from_sorted_list.rs b/src/solution/s0083_remove_duplicates_from_sorted_list.rs
similarity index 94%
rename from src/n0083_remove_duplicates_from_sorted_list.rs
rename to src/solution/s0083_remove_duplicates_from_sorted_list.rs
index b8fa539f..785cc03f 100644
--- a/src/n0083_remove_duplicates_from_sorted_list.rs
+++ b/src/solution/s0083_remove_duplicates_from_sorted_list.rs
@@ -19,7 +19,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0084_largest_rectangle_in_histogram.rs b/src/solution/s0084_largest_rectangle_in_histogram.rs
similarity index 100%
rename from src/n0084_largest_rectangle_in_histogram.rs
rename to src/solution/s0084_largest_rectangle_in_histogram.rs
diff --git a/src/n0085_maximal_rectangle.rs b/src/solution/s0085_maximal_rectangle.rs
similarity index 100%
rename from src/n0085_maximal_rectangle.rs
rename to src/solution/s0085_maximal_rectangle.rs
diff --git a/src/n0086_partition_list.rs b/src/solution/s0086_partition_list.rs
similarity index 97%
rename from src/n0086_partition_list.rs
rename to src/solution/s0086_partition_list.rs
index ad03b081..4238586f 100644
--- a/src/n0086_partition_list.rs
+++ b/src/solution/s0086_partition_list.rs
@@ -14,7 +14,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 impl Solution {
     pub fn partition(head: Option<Box<ListNode>>, x: i32) -> Option<Box<ListNode>> {
diff --git a/src/n0087_scramble_string.rs b/src/solution/s0087_scramble_string.rs
similarity index 100%
rename from src/n0087_scramble_string.rs
rename to src/solution/s0087_scramble_string.rs
diff --git a/src/n0088_merge_sorted_array.rs b/src/solution/s0088_merge_sorted_array.rs
similarity index 100%
rename from src/n0088_merge_sorted_array.rs
rename to src/solution/s0088_merge_sorted_array.rs
diff --git a/src/n0089_gray_code.rs b/src/solution/s0089_gray_code.rs
similarity index 100%
rename from src/n0089_gray_code.rs
rename to src/solution/s0089_gray_code.rs
diff --git a/src/n0090_subsets_ii.rs b/src/solution/s0090_subsets_ii.rs
similarity index 100%
rename from src/n0090_subsets_ii.rs
rename to src/solution/s0090_subsets_ii.rs
diff --git a/src/n0091_decode_ways.rs b/src/solution/s0091_decode_ways.rs
similarity index 100%
rename from src/n0091_decode_ways.rs
rename to src/solution/s0091_decode_ways.rs
diff --git a/src/n0092_reverse_linked_list_ii.rs b/src/solution/s0092_reverse_linked_list_ii.rs
similarity index 94%
rename from src/n0092_reverse_linked_list_ii.rs
rename to src/solution/s0092_reverse_linked_list_ii.rs
index 705a7875..e84035da 100644
--- a/src/n0092_reverse_linked_list_ii.rs
+++ b/src/solution/s0092_reverse_linked_list_ii.rs
@@ -14,7 +14,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0093_restore_ip_addresses.rs b/src/solution/s0093_restore_ip_addresses.rs
similarity index 100%
rename from src/n0093_restore_ip_addresses.rs
rename to src/solution/s0093_restore_ip_addresses.rs
diff --git a/src/n0094_binary_tree_inorder_traversal.rs b/src/solution/s0094_binary_tree_inorder_traversal.rs
similarity index 96%
rename from src/n0094_binary_tree_inorder_traversal.rs
rename to src/solution/s0094_binary_tree_inorder_traversal.rs
index c40cd1c8..d4d2ea2a 100644
--- a/src/n0094_binary_tree_inorder_traversal.rs
+++ b/src/solution/s0094_binary_tree_inorder_traversal.rs
@@ -22,7 +22,7 @@ pub struct Solution {}
 
 // submission codes start here
 
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 use std::cell::RefCell;
 use std::rc::Rc;
 impl Solution {
diff --git a/src/n0095_unique_binary_search_trees_ii.rs b/src/solution/s0095_unique_binary_search_trees_ii.rs
similarity index 97%
rename from src/n0095_unique_binary_search_trees_ii.rs
rename to src/solution/s0095_unique_binary_search_trees_ii.rs
index 3ab366e4..ffdc763b 100644
--- a/src/n0095_unique_binary_search_trees_ii.rs
+++ b/src/solution/s0095_unique_binary_search_trees_ii.rs
@@ -48,7 +48,7 @@ pub struct Solution {}
       / \
      2   4
  */
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 use std::cell::RefCell;
 use std::rc::Rc;
 impl Solution {
diff --git a/src/n0096_unique_binary_search_trees.rs b/src/solution/s0096_unique_binary_search_trees.rs
similarity index 100%
rename from src/n0096_unique_binary_search_trees.rs
rename to src/solution/s0096_unique_binary_search_trees.rs
diff --git a/src/n0097_interleaving_string.rs b/src/solution/s0097_interleaving_string.rs
similarity index 100%
rename from src/n0097_interleaving_string.rs
rename to src/solution/s0097_interleaving_string.rs
diff --git a/src/n0098_validate_binary_search_tree.rs b/src/solution/s0098_validate_binary_search_tree.rs
similarity index 98%
rename from src/n0098_validate_binary_search_tree.rs
rename to src/solution/s0098_validate_binary_search_tree.rs
index fcb359ee..7f55a47e 100644
--- a/src/n0098_validate_binary_search_tree.rs
+++ b/src/solution/s0098_validate_binary_search_tree.rs
@@ -40,7 +40,7 @@ pub struct Solution {}
 // submission codes start here
 
 // Definition for a binary tree node.
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 use std::cell::RefCell;
 use std::rc::Rc;
diff --git a/src/n0099_recover_binary_search_tree.rs b/src/solution/s0099_recover_binary_search_tree.rs
similarity index 95%
rename from src/n0099_recover_binary_search_tree.rs
rename to src/solution/s0099_recover_binary_search_tree.rs
index 8bc39b3d..3b92da04 100644
--- a/src/n0099_recover_binary_search_tree.rs
+++ b/src/solution/s0099_recover_binary_search_tree.rs
@@ -55,7 +55,7 @@
  */
 pub struct Solution {}
 
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0100_same_tree.rs b/src/solution/s0100_same_tree.rs
similarity index 96%
rename from src/n0100_same_tree.rs
rename to src/solution/s0100_same_tree.rs
index 51b7ad79..f1ca1972 100644
--- a/src/n0100_same_tree.rs
+++ b/src/solution/s0100_same_tree.rs
@@ -44,7 +44,7 @@
  */
 pub struct Solution {}
 
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 // submission codes start here
 use std::cell::RefCell;
 use std::rc::Rc;
diff --git a/src/n0101_symmetric_tree.rs b/src/solution/s0101_symmetric_tree.rs
similarity index 97%
rename from src/n0101_symmetric_tree.rs
rename to src/solution/s0101_symmetric_tree.rs
index d341ff34..c62962d2 100644
--- a/src/n0101_symmetric_tree.rs
+++ b/src/solution/s0101_symmetric_tree.rs
@@ -30,7 +30,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0102_binary_tree_level_order_traversal.rs b/src/solution/s0102_binary_tree_level_order_traversal.rs
similarity index 97%
rename from src/n0102_binary_tree_level_order_traversal.rs
rename to src/solution/s0102_binary_tree_level_order_traversal.rs
index 6fdabf6e..42f782a5 100644
--- a/src/n0102_binary_tree_level_order_traversal.rs
+++ b/src/solution/s0102_binary_tree_level_order_traversal.rs
@@ -26,7 +26,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0103_binary_tree_zigzag_level_order_traversal.rs b/src/solution/s0103_binary_tree_zigzag_level_order_traversal.rs
similarity index 97%
rename from src/n0103_binary_tree_zigzag_level_order_traversal.rs
rename to src/solution/s0103_binary_tree_zigzag_level_order_traversal.rs
index ce31b6b8..96476fda 100644
--- a/src/n0103_binary_tree_zigzag_level_order_traversal.rs
+++ b/src/solution/s0103_binary_tree_zigzag_level_order_traversal.rs
@@ -26,7 +26,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0104_maximum_depth_of_binary_tree.rs b/src/solution/s0104_maximum_depth_of_binary_tree.rs
similarity index 96%
rename from src/n0104_maximum_depth_of_binary_tree.rs
rename to src/solution/s0104_maximum_depth_of_binary_tree.rs
index c5faf233..6d2f18e6 100644
--- a/src/n0104_maximum_depth_of_binary_tree.rs
+++ b/src/solution/s0104_maximum_depth_of_binary_tree.rs
@@ -22,7 +22,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs b/src/solution/s0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs
similarity index 97%
rename from src/n0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs
rename to src/solution/s0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs
index 611725de..e271faa5 100644
--- a/src/n0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs
+++ b/src/solution/s0105_construct_binary_tree_from_preorder_and_inorder_traversal.rs
@@ -23,7 +23,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs b/src/solution/s0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs
similarity index 97%
rename from src/n0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs
rename to src/solution/s0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs
index 7d3e820c..63c469be 100644
--- a/src/n0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs
+++ b/src/solution/s0106_construct_binary_tree_from_inorder_and_postorder_traversal.rs
@@ -24,7 +24,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0107_binary_tree_level_order_traversal_ii.rs b/src/solution/s0107_binary_tree_level_order_traversal_ii.rs
similarity index 97%
rename from src/n0107_binary_tree_level_order_traversal_ii.rs
rename to src/solution/s0107_binary_tree_level_order_traversal_ii.rs
index 42855964..f77229a6 100644
--- a/src/n0107_binary_tree_level_order_traversal_ii.rs
+++ b/src/solution/s0107_binary_tree_level_order_traversal_ii.rs
@@ -26,7 +26,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0108_convert_sorted_array_to_binary_search_tree.rs b/src/solution/s0108_convert_sorted_array_to_binary_search_tree.rs
similarity index 97%
rename from src/n0108_convert_sorted_array_to_binary_search_tree.rs
rename to src/solution/s0108_convert_sorted_array_to_binary_search_tree.rs
index 4da33781..67e4b2ac 100644
--- a/src/n0108_convert_sorted_array_to_binary_search_tree.rs
+++ b/src/solution/s0108_convert_sorted_array_to_binary_search_tree.rs
@@ -21,7 +21,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0109_convert_sorted_list_to_binary_search_tree.rs b/src/solution/s0109_convert_sorted_list_to_binary_search_tree.rs
similarity index 94%
rename from src/n0109_convert_sorted_list_to_binary_search_tree.rs
rename to src/solution/s0109_convert_sorted_list_to_binary_search_tree.rs
index 072c6eac..6bb37b0e 100644
--- a/src/n0109_convert_sorted_list_to_binary_search_tree.rs
+++ b/src/solution/s0109_convert_sorted_list_to_binary_search_tree.rs
@@ -21,8 +21,8 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::linked_list::{to_list, ListNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0110_balanced_binary_tree.rs b/src/solution/s0110_balanced_binary_tree.rs
similarity index 93%
rename from src/n0110_balanced_binary_tree.rs
rename to src/solution/s0110_balanced_binary_tree.rs
index 68e1b2ad..bb067d02 100644
--- a/src/n0110_balanced_binary_tree.rs
+++ b/src/solution/s0110_balanced_binary_tree.rs
@@ -40,7 +40,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0111_minimum_depth_of_binary_tree.rs b/src/solution/s0111_minimum_depth_of_binary_tree.rs
similarity index 96%
rename from src/n0111_minimum_depth_of_binary_tree.rs
rename to src/solution/s0111_minimum_depth_of_binary_tree.rs
index f537c316..1efb759d 100644
--- a/src/n0111_minimum_depth_of_binary_tree.rs
+++ b/src/solution/s0111_minimum_depth_of_binary_tree.rs
@@ -22,7 +22,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0112_path_sum.rs b/src/solution/s0112_path_sum.rs
similarity index 97%
rename from src/n0112_path_sum.rs
rename to src/solution/s0112_path_sum.rs
index 72e34da0..2f036b21 100644
--- a/src/n0112_path_sum.rs
+++ b/src/solution/s0112_path_sum.rs
@@ -23,7 +23,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0113_path_sum_ii.rs b/src/solution/s0113_path_sum_ii.rs
similarity index 97%
rename from src/n0113_path_sum_ii.rs
rename to src/solution/s0113_path_sum_ii.rs
index c9914e08..d567e693 100644
--- a/src/n0113_path_sum_ii.rs
+++ b/src/solution/s0113_path_sum_ii.rs
@@ -30,7 +30,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0114_flatten_binary_tree_to_linked_list.rs b/src/solution/s0114_flatten_binary_tree_to_linked_list.rs
similarity index 97%
rename from src/n0114_flatten_binary_tree_to_linked_list.rs
rename to src/solution/s0114_flatten_binary_tree_to_linked_list.rs
index 2b46cd42..9661e9e7 100644
--- a/src/n0114_flatten_binary_tree_to_linked_list.rs
+++ b/src/solution/s0114_flatten_binary_tree_to_linked_list.rs
@@ -31,7 +31,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0115_distinct_subsequences.rs b/src/solution/s0115_distinct_subsequences.rs
similarity index 100%
rename from src/n0115_distinct_subsequences.rs
rename to src/solution/s0115_distinct_subsequences.rs
diff --git a/src/n0118_pascals_triangle.rs b/src/solution/s0118_pascals_triangle.rs
similarity index 100%
rename from src/n0118_pascals_triangle.rs
rename to src/solution/s0118_pascals_triangle.rs
diff --git a/src/n0119_pascals_triangle_ii.rs b/src/solution/s0119_pascals_triangle_ii.rs
similarity index 100%
rename from src/n0119_pascals_triangle_ii.rs
rename to src/solution/s0119_pascals_triangle_ii.rs
diff --git a/src/n0120_triangle.rs b/src/solution/s0120_triangle.rs
similarity index 100%
rename from src/n0120_triangle.rs
rename to src/solution/s0120_triangle.rs
diff --git a/src/n0121_best_time_to_buy_and_sell_stock.rs b/src/solution/s0121_best_time_to_buy_and_sell_stock.rs
similarity index 100%
rename from src/n0121_best_time_to_buy_and_sell_stock.rs
rename to src/solution/s0121_best_time_to_buy_and_sell_stock.rs
diff --git a/src/n0122_best_time_to_buy_and_sell_stock_ii.rs b/src/solution/s0122_best_time_to_buy_and_sell_stock_ii.rs
similarity index 100%
rename from src/n0122_best_time_to_buy_and_sell_stock_ii.rs
rename to src/solution/s0122_best_time_to_buy_and_sell_stock_ii.rs
diff --git a/src/n0123_best_time_to_buy_and_sell_stock_iii.rs b/src/solution/s0123_best_time_to_buy_and_sell_stock_iii.rs
similarity index 100%
rename from src/n0123_best_time_to_buy_and_sell_stock_iii.rs
rename to src/solution/s0123_best_time_to_buy_and_sell_stock_iii.rs
diff --git a/src/n0124_binary_tree_maximum_path_sum.rs b/src/solution/s0124_binary_tree_maximum_path_sum.rs
similarity index 98%
rename from src/n0124_binary_tree_maximum_path_sum.rs
rename to src/solution/s0124_binary_tree_maximum_path_sum.rs
index 5517d18f..f76f3178 100644
--- a/src/n0124_binary_tree_maximum_path_sum.rs
+++ b/src/solution/s0124_binary_tree_maximum_path_sum.rs
@@ -33,7 +33,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0125_valid_palindrome.rs b/src/solution/s0125_valid_palindrome.rs
similarity index 100%
rename from src/n0125_valid_palindrome.rs
rename to src/solution/s0125_valid_palindrome.rs
diff --git a/src/n0126_word_ladder_ii.rs b/src/solution/s0126_word_ladder_ii.rs
similarity index 100%
rename from src/n0126_word_ladder_ii.rs
rename to src/solution/s0126_word_ladder_ii.rs
diff --git a/src/n0127_word_ladder.rs b/src/solution/s0127_word_ladder.rs
similarity index 100%
rename from src/n0127_word_ladder.rs
rename to src/solution/s0127_word_ladder.rs
diff --git a/src/n0128_longest_consecutive_sequence.rs b/src/solution/s0128_longest_consecutive_sequence.rs
similarity index 100%
rename from src/n0128_longest_consecutive_sequence.rs
rename to src/solution/s0128_longest_consecutive_sequence.rs
diff --git a/src/n0129_sum_root_to_leaf_numbers.rs b/src/solution/s0129_sum_root_to_leaf_numbers.rs
similarity index 97%
rename from src/n0129_sum_root_to_leaf_numbers.rs
rename to src/solution/s0129_sum_root_to_leaf_numbers.rs
index 5e423c34..c52dc94c 100644
--- a/src/n0129_sum_root_to_leaf_numbers.rs
+++ b/src/solution/s0129_sum_root_to_leaf_numbers.rs
@@ -40,7 +40,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0130_surrounded_regions.rs b/src/solution/s0130_surrounded_regions.rs
similarity index 100%
rename from src/n0130_surrounded_regions.rs
rename to src/solution/s0130_surrounded_regions.rs
diff --git a/src/n0131_palindrome_partitioning.rs b/src/solution/s0131_palindrome_partitioning.rs
similarity index 100%
rename from src/n0131_palindrome_partitioning.rs
rename to src/solution/s0131_palindrome_partitioning.rs
diff --git a/src/n0132_palindrome_partitioning_ii.rs b/src/solution/s0132_palindrome_partitioning_ii.rs
similarity index 100%
rename from src/n0132_palindrome_partitioning_ii.rs
rename to src/solution/s0132_palindrome_partitioning_ii.rs
diff --git a/src/n0134_gas_station.rs b/src/solution/s0134_gas_station.rs
similarity index 100%
rename from src/n0134_gas_station.rs
rename to src/solution/s0134_gas_station.rs
diff --git a/src/n0135_candy.rs b/src/solution/s0135_candy.rs
similarity index 100%
rename from src/n0135_candy.rs
rename to src/solution/s0135_candy.rs
diff --git a/src/n0136_single_number.rs b/src/solution/s0136_single_number.rs
similarity index 100%
rename from src/n0136_single_number.rs
rename to src/solution/s0136_single_number.rs
diff --git a/src/n0137_single_number_ii.rs b/src/solution/s0137_single_number_ii.rs
similarity index 100%
rename from src/n0137_single_number_ii.rs
rename to src/solution/s0137_single_number_ii.rs
diff --git a/src/n0139_word_break.rs b/src/solution/s0139_word_break.rs
similarity index 100%
rename from src/n0139_word_break.rs
rename to src/solution/s0139_word_break.rs
diff --git a/src/n0140_word_break_ii.rs b/src/solution/s0140_word_break_ii.rs
similarity index 100%
rename from src/n0140_word_break_ii.rs
rename to src/solution/s0140_word_break_ii.rs
diff --git a/src/n0143_reorder_list.rs b/src/solution/s0143_reorder_list.rs
similarity index 93%
rename from src/n0143_reorder_list.rs
rename to src/solution/s0143_reorder_list.rs
index 169c44d1..06ec32af 100644
--- a/src/n0143_reorder_list.rs
+++ b/src/solution/s0143_reorder_list.rs
@@ -19,7 +19,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0144_binary_tree_preorder_traversal.rs b/src/solution/s0144_binary_tree_preorder_traversal.rs
similarity index 96%
rename from src/n0144_binary_tree_preorder_traversal.rs
rename to src/solution/s0144_binary_tree_preorder_traversal.rs
index 951014c6..02ed1f7a 100644
--- a/src/n0144_binary_tree_preorder_traversal.rs
+++ b/src/solution/s0144_binary_tree_preorder_traversal.rs
@@ -20,7 +20,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0145_binary_tree_postorder_traversal.rs b/src/solution/s0145_binary_tree_postorder_traversal.rs
similarity index 96%
rename from src/n0145_binary_tree_postorder_traversal.rs
rename to src/solution/s0145_binary_tree_postorder_traversal.rs
index 66495658..2670b5bd 100644
--- a/src/n0145_binary_tree_postorder_traversal.rs
+++ b/src/solution/s0145_binary_tree_postorder_traversal.rs
@@ -20,7 +20,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0146_lru_cache.rs b/src/solution/s0146_lru_cache.rs
similarity index 100%
rename from src/n0146_lru_cache.rs
rename to src/solution/s0146_lru_cache.rs
diff --git a/src/n0147_insertion_sort_list.rs b/src/solution/s0147_insertion_sort_list.rs
similarity index 96%
rename from src/n0147_insertion_sort_list.rs
rename to src/solution/s0147_insertion_sort_list.rs
index edcd0787..cdcd2d69 100644
--- a/src/n0147_insertion_sort_list.rs
+++ b/src/solution/s0147_insertion_sort_list.rs
@@ -9,7 +9,7 @@
  * <img alt="" src="https://upload.wikimedia.org/wikipedia/commons/0/0f/Insertion-sort-example-300px.gif" style="height:180px; width:300px" /><br />
  * <small>A graphical example of insertion sort. The partial sorted list (black) initially contains only the first element in the list.<br />
  * With each iteration one element (red) is removed from the input data and inserted in-place into the sorted list</small><br />
- *  
+ *
  *
  * <ol>
  * </ol>
@@ -39,7 +39,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0148_sort_list.rs b/src/solution/s0148_sort_list.rs
similarity index 98%
rename from src/n0148_sort_list.rs
rename to src/solution/s0148_sort_list.rs
index 5fd6a8a2..4bc8ac17 100644
--- a/src/n0148_sort_list.rs
+++ b/src/solution/s0148_sort_list.rs
@@ -18,7 +18,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0149_max_points_on_a_line.rs b/src/solution/s0149_max_points_on_a_line.rs
similarity index 95%
rename from src/n0149_max_points_on_a_line.rs
rename to src/solution/s0149_max_points_on_a_line.rs
index dff94777..c2faf93b 100644
--- a/src/n0149_max_points_on_a_line.rs
+++ b/src/solution/s0149_max_points_on_a_line.rs
@@ -13,7 +13,7 @@
  * |
  * |        o
  * |     o
- * |  o  
+ * |  o
  * +------------->
  * 0  1  2  3  4
  *
@@ -36,7 +36,7 @@
  *
  */
 pub struct Solution {}
-use super::util::point::Point;
+use crate::util::point::Point;
 
 /*
 要回顾下高中数学：已知两点, 求解一般式:
diff --git a/src/n0150_evaluate_reverse_polish_notation.rs b/src/solution/s0150_evaluate_reverse_polish_notation.rs
similarity index 100%
rename from src/n0150_evaluate_reverse_polish_notation.rs
rename to src/solution/s0150_evaluate_reverse_polish_notation.rs
diff --git a/src/n0151_reverse_words_in_a_string.rs b/src/solution/s0151_reverse_words_in_a_string.rs
similarity index 100%
rename from src/n0151_reverse_words_in_a_string.rs
rename to src/solution/s0151_reverse_words_in_a_string.rs
diff --git a/src/n0152_maximum_product_subarray.rs b/src/solution/s0152_maximum_product_subarray.rs
similarity index 100%
rename from src/n0152_maximum_product_subarray.rs
rename to src/solution/s0152_maximum_product_subarray.rs
diff --git a/src/n0153_find_minimum_in_rotated_sorted_array.rs b/src/solution/s0153_find_minimum_in_rotated_sorted_array.rs
similarity index 100%
rename from src/n0153_find_minimum_in_rotated_sorted_array.rs
rename to src/solution/s0153_find_minimum_in_rotated_sorted_array.rs
diff --git a/src/n0154_find_minimum_in_rotated_sorted_array_ii.rs b/src/solution/s0154_find_minimum_in_rotated_sorted_array_ii.rs
similarity index 100%
rename from src/n0154_find_minimum_in_rotated_sorted_array_ii.rs
rename to src/solution/s0154_find_minimum_in_rotated_sorted_array_ii.rs
diff --git a/src/n0155_min_stack.rs b/src/solution/s0155_min_stack.rs
similarity index 100%
rename from src/n0155_min_stack.rs
rename to src/solution/s0155_min_stack.rs
diff --git a/src/n0162_find_peak_element.rs b/src/solution/s0162_find_peak_element.rs
similarity index 100%
rename from src/n0162_find_peak_element.rs
rename to src/solution/s0162_find_peak_element.rs
diff --git a/src/n0164_maximum_gap.rs b/src/solution/s0164_maximum_gap.rs
similarity index 100%
rename from src/n0164_maximum_gap.rs
rename to src/solution/s0164_maximum_gap.rs
diff --git a/src/n0165_compare_version_numbers.rs b/src/solution/s0165_compare_version_numbers.rs
similarity index 100%
rename from src/n0165_compare_version_numbers.rs
rename to src/solution/s0165_compare_version_numbers.rs
diff --git a/src/n0166_fraction_to_recurring_decimal.rs b/src/solution/s0166_fraction_to_recurring_decimal.rs
similarity index 100%
rename from src/n0166_fraction_to_recurring_decimal.rs
rename to src/solution/s0166_fraction_to_recurring_decimal.rs
diff --git a/src/n0167_two_sum_ii_input_array_is_sorted.rs b/src/solution/s0167_two_sum_ii_input_array_is_sorted.rs
similarity index 100%
rename from src/n0167_two_sum_ii_input_array_is_sorted.rs
rename to src/solution/s0167_two_sum_ii_input_array_is_sorted.rs
diff --git a/src/n0168_excel_sheet_column_title.rs b/src/solution/s0168_excel_sheet_column_title.rs
similarity index 100%
rename from src/n0168_excel_sheet_column_title.rs
rename to src/solution/s0168_excel_sheet_column_title.rs
diff --git a/src/n0169_majority_element.rs b/src/solution/s0169_majority_element.rs
similarity index 100%
rename from src/n0169_majority_element.rs
rename to src/solution/s0169_majority_element.rs
diff --git a/src/n0171_excel_sheet_column_number.rs b/src/solution/s0171_excel_sheet_column_number.rs
similarity index 100%
rename from src/n0171_excel_sheet_column_number.rs
rename to src/solution/s0171_excel_sheet_column_number.rs
diff --git a/src/n0172_factorial_trailing_zeroes.rs b/src/solution/s0172_factorial_trailing_zeroes.rs
similarity index 100%
rename from src/n0172_factorial_trailing_zeroes.rs
rename to src/solution/s0172_factorial_trailing_zeroes.rs
diff --git a/src/n0173_binary_search_tree_iterator.rs b/src/solution/s0173_binary_search_tree_iterator.rs
similarity index 94%
rename from src/n0173_binary_search_tree_iterator.rs
rename to src/solution/s0173_binary_search_tree_iterator.rs
index 582e922a..caef4724 100644
--- a/src/n0173_binary_search_tree_iterator.rs
+++ b/src/solution/s0173_binary_search_tree_iterator.rs
@@ -5,7 +5,7 @@
  *
  * Calling next() will return the next smallest number in the BST.
  *
- *  
+ *
  *
  *
  *
@@ -27,7 +27,7 @@
  * iterator.hasNext(); // return false
  *
  *
- *  
+ *
  *
  * Note:
  *
@@ -38,7 +38,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 use std::cell::RefCell;
 use std::rc::Rc;
 
diff --git a/src/n0174_dungeon_game.rs b/src/solution/s0174_dungeon_game.rs
similarity index 100%
rename from src/n0174_dungeon_game.rs
rename to src/solution/s0174_dungeon_game.rs
diff --git a/src/n0179_largest_number.rs b/src/solution/s0179_largest_number.rs
similarity index 100%
rename from src/n0179_largest_number.rs
rename to src/solution/s0179_largest_number.rs
diff --git a/src/n0187_repeated_dna_sequences.rs b/src/solution/s0187_repeated_dna_sequences.rs
similarity index 100%
rename from src/n0187_repeated_dna_sequences.rs
rename to src/solution/s0187_repeated_dna_sequences.rs
diff --git a/src/n0188_best_time_to_buy_and_sell_stock_iv.rs b/src/solution/s0188_best_time_to_buy_and_sell_stock_iv.rs
similarity index 100%
rename from src/n0188_best_time_to_buy_and_sell_stock_iv.rs
rename to src/solution/s0188_best_time_to_buy_and_sell_stock_iv.rs
diff --git a/src/n0189_rotate_array.rs b/src/solution/s0189_rotate_array.rs
similarity index 100%
rename from src/n0189_rotate_array.rs
rename to src/solution/s0189_rotate_array.rs
diff --git a/src/n0198_house_robber.rs b/src/solution/s0198_house_robber.rs
similarity index 100%
rename from src/n0198_house_robber.rs
rename to src/solution/s0198_house_robber.rs
diff --git a/src/n0199_binary_tree_right_side_view.rs b/src/solution/s0199_binary_tree_right_side_view.rs
similarity index 97%
rename from src/n0199_binary_tree_right_side_view.rs
rename to src/solution/s0199_binary_tree_right_side_view.rs
index 403a3404..c580970c 100644
--- a/src/n0199_binary_tree_right_side_view.rs
+++ b/src/solution/s0199_binary_tree_right_side_view.rs
@@ -18,7 +18,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0200_number_of_islands.rs b/src/solution/s0200_number_of_islands.rs
similarity index 100%
rename from src/n0200_number_of_islands.rs
rename to src/solution/s0200_number_of_islands.rs
diff --git a/src/n0201_bitwise_and_of_numbers_range.rs b/src/solution/s0201_bitwise_and_of_numbers_range.rs
similarity index 100%
rename from src/n0201_bitwise_and_of_numbers_range.rs
rename to src/solution/s0201_bitwise_and_of_numbers_range.rs
diff --git a/src/n0202_happy_number.rs b/src/solution/s0202_happy_number.rs
similarity index 100%
rename from src/n0202_happy_number.rs
rename to src/solution/s0202_happy_number.rs
diff --git a/src/n0203_remove_linked_list_elements.rs b/src/solution/s0203_remove_linked_list_elements.rs
similarity index 95%
rename from src/n0203_remove_linked_list_elements.rs
rename to src/solution/s0203_remove_linked_list_elements.rs
index 290923d6..f8d9bc43 100644
--- a/src/n0203_remove_linked_list_elements.rs
+++ b/src/solution/s0203_remove_linked_list_elements.rs
@@ -12,7 +12,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0204_count_primes.rs b/src/solution/s0204_count_primes.rs
similarity index 100%
rename from src/n0204_count_primes.rs
rename to src/solution/s0204_count_primes.rs
diff --git a/src/n0205_isomorphic_strings.rs b/src/solution/s0205_isomorphic_strings.rs
similarity index 100%
rename from src/n0205_isomorphic_strings.rs
rename to src/solution/s0205_isomorphic_strings.rs
diff --git a/src/n0206_reverse_linked_list.rs b/src/solution/s0206_reverse_linked_list.rs
similarity index 94%
rename from src/n0206_reverse_linked_list.rs
rename to src/solution/s0206_reverse_linked_list.rs
index bdbe34e4..4689f415 100644
--- a/src/n0206_reverse_linked_list.rs
+++ b/src/solution/s0206_reverse_linked_list.rs
@@ -16,7 +16,7 @@
  *
  */
 pub struct Solution {}
-use super::util::linked_list::{to_list, ListNode};
+use crate::util::linked_list::{to_list, ListNode};
 
 // submission codes start here
 
diff --git a/src/n0207_course_schedule.rs b/src/solution/s0207_course_schedule.rs
similarity index 100%
rename from src/n0207_course_schedule.rs
rename to src/solution/s0207_course_schedule.rs
diff --git a/src/n0208_implement_trie_prefix_tree.rs b/src/solution/s0208_implement_trie_prefix_tree.rs
similarity index 100%
rename from src/n0208_implement_trie_prefix_tree.rs
rename to src/solution/s0208_implement_trie_prefix_tree.rs
diff --git a/src/n0209_minimum_size_subarray_sum.rs b/src/solution/s0209_minimum_size_subarray_sum.rs
similarity index 100%
rename from src/n0209_minimum_size_subarray_sum.rs
rename to src/solution/s0209_minimum_size_subarray_sum.rs
diff --git a/src/n0210_course_schedule_ii.rs b/src/solution/s0210_course_schedule_ii.rs
similarity index 100%
rename from src/n0210_course_schedule_ii.rs
rename to src/solution/s0210_course_schedule_ii.rs
diff --git a/src/n0211_add_and_search_word_data_structure_design.rs b/src/solution/s0211_add_and_search_word_data_structure_design.rs
similarity index 100%
rename from src/n0211_add_and_search_word_data_structure_design.rs
rename to src/solution/s0211_add_and_search_word_data_structure_design.rs
diff --git a/src/n0212_word_search_ii.rs b/src/solution/s0212_word_search_ii.rs
similarity index 100%
rename from src/n0212_word_search_ii.rs
rename to src/solution/s0212_word_search_ii.rs
diff --git a/src/n0213_house_robber_ii.rs b/src/solution/s0213_house_robber_ii.rs
similarity index 100%
rename from src/n0213_house_robber_ii.rs
rename to src/solution/s0213_house_robber_ii.rs
diff --git a/src/n0214_shortest_palindrome.rs b/src/solution/s0214_shortest_palindrome.rs
similarity index 100%
rename from src/n0214_shortest_palindrome.rs
rename to src/solution/s0214_shortest_palindrome.rs
diff --git a/src/n0215_kth_largest_element_in_an_array.rs b/src/solution/s0215_kth_largest_element_in_an_array.rs
similarity index 100%
rename from src/n0215_kth_largest_element_in_an_array.rs
rename to src/solution/s0215_kth_largest_element_in_an_array.rs
diff --git a/src/n0216_combination_sum_iii.rs b/src/solution/s0216_combination_sum_iii.rs
similarity index 100%
rename from src/n0216_combination_sum_iii.rs
rename to src/solution/s0216_combination_sum_iii.rs
diff --git a/src/n0217_contains_duplicate.rs b/src/solution/s0217_contains_duplicate.rs
similarity index 100%
rename from src/n0217_contains_duplicate.rs
rename to src/solution/s0217_contains_duplicate.rs
diff --git a/src/n0218_the_skyline_problem.rs b/src/solution/s0218_the_skyline_problem.rs
similarity index 100%
rename from src/n0218_the_skyline_problem.rs
rename to src/solution/s0218_the_skyline_problem.rs
diff --git a/src/n0219_contains_duplicate_ii.rs b/src/solution/s0219_contains_duplicate_ii.rs
similarity index 100%
rename from src/n0219_contains_duplicate_ii.rs
rename to src/solution/s0219_contains_duplicate_ii.rs
diff --git a/src/n0220_contains_duplicate_iii.rs b/src/solution/s0220_contains_duplicate_iii.rs
similarity index 100%
rename from src/n0220_contains_duplicate_iii.rs
rename to src/solution/s0220_contains_duplicate_iii.rs
diff --git a/src/n0221_maximal_square.rs b/src/solution/s0221_maximal_square.rs
similarity index 100%
rename from src/n0221_maximal_square.rs
rename to src/solution/s0221_maximal_square.rs
diff --git a/src/n0222_count_complete_tree_nodes.rs b/src/solution/s0222_count_complete_tree_nodes.rs
similarity index 98%
rename from src/n0222_count_complete_tree_nodes.rs
rename to src/solution/s0222_count_complete_tree_nodes.rs
index c511399d..189fb3dd 100644
--- a/src/n0222_count_complete_tree_nodes.rs
+++ b/src/solution/s0222_count_complete_tree_nodes.rs
@@ -22,7 +22,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0223_rectangle_area.rs b/src/solution/s0223_rectangle_area.rs
similarity index 100%
rename from src/n0223_rectangle_area.rs
rename to src/solution/s0223_rectangle_area.rs
diff --git a/src/n0224_basic_calculator.rs b/src/solution/s0224_basic_calculator.rs
similarity index 100%
rename from src/n0224_basic_calculator.rs
rename to src/solution/s0224_basic_calculator.rs
diff --git a/src/n0225_implement_stack_using_queues.rs b/src/solution/s0225_implement_stack_using_queues.rs
similarity index 100%
rename from src/n0225_implement_stack_using_queues.rs
rename to src/solution/s0225_implement_stack_using_queues.rs
diff --git a/src/n0226_invert_binary_tree.rs b/src/solution/s0226_invert_binary_tree.rs
similarity index 97%
rename from src/n0226_invert_binary_tree.rs
rename to src/solution/s0226_invert_binary_tree.rs
index 29e2a953..30bd001a 100644
--- a/src/n0226_invert_binary_tree.rs
+++ b/src/solution/s0226_invert_binary_tree.rs
@@ -30,7 +30,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0227_basic_calculator_ii.rs b/src/solution/s0227_basic_calculator_ii.rs
similarity index 100%
rename from src/n0227_basic_calculator_ii.rs
rename to src/solution/s0227_basic_calculator_ii.rs
diff --git a/src/n0228_summary_ranges.rs b/src/solution/s0228_summary_ranges.rs
similarity index 100%
rename from src/n0228_summary_ranges.rs
rename to src/solution/s0228_summary_ranges.rs
diff --git a/src/n0229_majority_element_ii.rs b/src/solution/s0229_majority_element_ii.rs
similarity index 100%
rename from src/n0229_majority_element_ii.rs
rename to src/solution/s0229_majority_element_ii.rs
diff --git a/src/n0230_kth_smallest_element_in_a_bst.rs b/src/solution/s0230_kth_smallest_element_in_a_bst.rs
similarity index 97%
rename from src/n0230_kth_smallest_element_in_a_bst.rs
rename to src/solution/s0230_kth_smallest_element_in_a_bst.rs
index 65de4484..fe14721f 100644
--- a/src/n0230_kth_smallest_element_in_a_bst.rs
+++ b/src/solution/s0230_kth_smallest_element_in_a_bst.rs
@@ -36,7 +36,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0231_power_of_two.rs b/src/solution/s0231_power_of_two.rs
similarity index 100%
rename from src/n0231_power_of_two.rs
rename to src/solution/s0231_power_of_two.rs
diff --git a/src/n0232_implement_queue_using_stacks.rs b/src/solution/s0232_implement_queue_using_stacks.rs
similarity index 100%
rename from src/n0232_implement_queue_using_stacks.rs
rename to src/solution/s0232_implement_queue_using_stacks.rs
diff --git a/src/n0233_number_of_digit_one.rs b/src/solution/s0233_number_of_digit_one.rs
similarity index 100%
rename from src/n0233_number_of_digit_one.rs
rename to src/solution/s0233_number_of_digit_one.rs
diff --git a/src/n0238_product_of_array_except_self.rs b/src/solution/s0238_product_of_array_except_self.rs
similarity index 100%
rename from src/n0238_product_of_array_except_self.rs
rename to src/solution/s0238_product_of_array_except_self.rs
diff --git a/src/n0239_sliding_window_maximum.rs b/src/solution/s0239_sliding_window_maximum.rs
similarity index 100%
rename from src/n0239_sliding_window_maximum.rs
rename to src/solution/s0239_sliding_window_maximum.rs
diff --git a/src/n0241_different_ways_to_add_parentheses.rs b/src/solution/s0241_different_ways_to_add_parentheses.rs
similarity index 100%
rename from src/n0241_different_ways_to_add_parentheses.rs
rename to src/solution/s0241_different_ways_to_add_parentheses.rs
diff --git a/src/n0242_valid_anagram.rs b/src/solution/s0242_valid_anagram.rs
similarity index 100%
rename from src/n0242_valid_anagram.rs
rename to src/solution/s0242_valid_anagram.rs
diff --git a/src/n0257_binary_tree_paths.rs b/src/solution/s0257_binary_tree_paths.rs
similarity index 97%
rename from src/n0257_binary_tree_paths.rs
rename to src/solution/s0257_binary_tree_paths.rs
index ef5254c9..c5d6d336 100644
--- a/src/n0257_binary_tree_paths.rs
+++ b/src/solution/s0257_binary_tree_paths.rs
@@ -22,7 +22,7 @@
  *
  */
 pub struct Solution {}
-use super::util::tree::{to_tree, TreeNode};
+use crate::util::tree::{to_tree, TreeNode};
 
 // submission codes start here
 
diff --git a/src/n0258_add_digits.rs b/src/solution/s0258_add_digits.rs
similarity index 100%
rename from src/n0258_add_digits.rs
rename to src/solution/s0258_add_digits.rs
diff --git a/src/n0260_single_number_iii.rs b/src/solution/s0260_single_number_iii.rs
similarity index 100%
rename from src/n0260_single_number_iii.rs
rename to src/solution/s0260_single_number_iii.rs
diff --git a/src/n0263_ugly_number.rs b/src/solution/s0263_ugly_number.rs
similarity index 100%
rename from src/n0263_ugly_number.rs
rename to src/solution/s0263_ugly_number.rs
diff --git a/src/n0264_ugly_number_ii.rs b/src/solution/s0264_ugly_number_ii.rs
similarity index 100%
rename from src/n0264_ugly_number_ii.rs
rename to src/solution/s0264_ugly_number_ii.rs
diff --git a/src/n0268_missing_number.rs b/src/solution/s0268_missing_number.rs
similarity index 100%
rename from src/n0268_missing_number.rs
rename to src/solution/s0268_missing_number.rs
diff --git a/src/n0273_integer_to_english_words.rs b/src/solution/s0273_integer_to_english_words.rs
similarity index 100%
rename from src/n0273_integer_to_english_words.rs
rename to src/solution/s0273_integer_to_english_words.rs
diff --git a/src/n0274_h_index.rs b/src/solution/s0274_h_index.rs
similarity index 100%
rename from src/n0274_h_index.rs
rename to src/solution/s0274_h_index.rs
diff --git a/src/n0275_h_index_ii.rs b/src/solution/s0275_h_index_ii.rs
similarity index 100%
rename from src/n0275_h_index_ii.rs
rename to src/solution/s0275_h_index_ii.rs
diff --git a/src/n0279_perfect_squares.rs b/src/solution/s0279_perfect_squares.rs
similarity index 100%
rename from src/n0279_perfect_squares.rs
rename to src/solution/s0279_perfect_squares.rs
diff --git a/src/n0282_expression_add_operators.rs b/src/solution/s0282_expression_add_operators.rs
similarity index 100%
rename from src/n0282_expression_add_operators.rs
rename to src/solution/s0282_expression_add_operators.rs
diff --git a/src/n0283_move_zeroes.rs b/src/solution/s0283_move_zeroes.rs
similarity index 100%
rename from src/n0283_move_zeroes.rs
rename to src/solution/s0283_move_zeroes.rs
diff --git a/src/n0287_find_the_duplicate_number.rs b/src/solution/s0287_find_the_duplicate_number.rs
similarity index 100%
rename from src/n0287_find_the_duplicate_number.rs
rename to src/solution/s0287_find_the_duplicate_number.rs
diff --git a/src/n0289_game_of_life.rs b/src/solution/s0289_game_of_life.rs
similarity index 100%
rename from src/n0289_game_of_life.rs
rename to src/solution/s0289_game_of_life.rs
diff --git a/src/n0290_word_pattern.rs b/src/solution/s0290_word_pattern.rs
similarity index 100%
rename from src/n0290_word_pattern.rs
rename to src/solution/s0290_word_pattern.rs
diff --git a/src/n0292_nim_game.rs b/src/solution/s0292_nim_game.rs
similarity index 100%
rename from src/n0292_nim_game.rs
rename to src/solution/s0292_nim_game.rs
diff --git a/src/n0295_find_median_from_data_stream.rs b/src/solution/s0295_find_median_from_data_stream.rs
similarity index 100%
rename from src/n0295_find_median_from_data_stream.rs
rename to src/solution/s0295_find_median_from_data_stream.rs
diff --git a/src/n0299_bulls_and_cows.rs b/src/solution/s0299_bulls_and_cows.rs
similarity index 100%
rename from src/n0299_bulls_and_cows.rs
rename to src/solution/s0299_bulls_and_cows.rs
diff --git a/src/n0300_longest_increasing_subsequence.rs b/src/solution/s0300_longest_increasing_subsequence.rs
similarity index 100%
rename from src/n0300_longest_increasing_subsequence.rs
rename to src/solution/s0300_longest_increasing_subsequence.rs
diff --git a/src/n0301_remove_invalid_parentheses.rs b/src/solution/s0301_remove_invalid_parentheses.rs
similarity index 100%
rename from src/n0301_remove_invalid_parentheses.rs
rename to src/solution/s0301_remove_invalid_parentheses.rs
diff --git a/src/n0303_range_sum_query_immutable.rs b/src/solution/s0303_range_sum_query_immutable.rs
similarity index 100%
rename from src/n0303_range_sum_query_immutable.rs
rename to src/solution/s0303_range_sum_query_immutable.rs
diff --git a/src/n0304_range_sum_query_2d_immutable.rs b/src/solution/s0304_range_sum_query_2d_immutable.rs
similarity index 100%
rename from src/n0304_range_sum_query_2d_immutable.rs
rename to src/solution/s0304_range_sum_query_2d_immutable.rs
diff --git a/src/n0306_additive_number.rs b/src/solution/s0306_additive_number.rs
similarity index 100%
rename from src/n0306_additive_number.rs
rename to src/solution/s0306_additive_number.rs
diff --git a/src/n0307_range_sum_query_mutable.rs b/src/solution/s0307_range_sum_query_mutable.rs
similarity index 100%
rename from src/n0307_range_sum_query_mutable.rs
rename to src/solution/s0307_range_sum_query_mutable.rs
diff --git a/src/n0309_best_time_to_buy_and_sell_stock_with_cooldown.rs b/src/solution/s0309_best_time_to_buy_and_sell_stock_with_cooldown.rs
similarity index 100%
rename from src/n0309_best_time_to_buy_and_sell_stock_with_cooldown.rs
rename to src/solution/s0309_best_time_to_buy_and_sell_stock_with_cooldown.rs
diff --git a/src/n0310_minimum_height_trees.rs b/src/solution/s0310_minimum_height_trees.rs
similarity index 100%
rename from src/n0310_minimum_height_trees.rs
rename to src/solution/s0310_minimum_height_trees.rs
diff --git a/src/n0312_burst_balloons.rs b/src/solution/s0312_burst_balloons.rs
similarity index 100%
rename from src/n0312_burst_balloons.rs
rename to src/solution/s0312_burst_balloons.rs
diff --git a/src/n0313_super_ugly_number.rs b/src/solution/s0313_super_ugly_number.rs
similarity index 100%
rename from src/n0313_super_ugly_number.rs
rename to src/solution/s0313_super_ugly_number.rs
diff --git a/src/n0509_fibonacci_number.rs b/src/solution/s0509_fibonacci_number.rs
similarity index 100%
rename from src/n0509_fibonacci_number.rs
rename to src/solution/s0509_fibonacci_number.rs
diff --git a/src/n0704_binary_search.rs b/src/solution/s0704_binary_search.rs
similarity index 100%
rename from src/n0704_binary_search.rs
rename to src/solution/s0704_binary_search.rs
diff --git a/src/n0969_pancake_sorting.rs b/src/solution/s0969_pancake_sorting.rs
similarity index 100%
rename from src/n0969_pancake_sorting.rs
rename to src/solution/s0969_pancake_sorting.rs
diff --git a/src/n1018_binary_prefix_divisible_by_5.rs b/src/solution/s1018_binary_prefix_divisible_by_5.rs
similarity index 100%
rename from src/n1018_binary_prefix_divisible_by_5.rs
rename to src/solution/s1018_binary_prefix_divisible_by_5.rs
diff --git a/src/n1046_last_stone_weight.rs b/src/solution/s1046_last_stone_weight.rs
similarity index 100%
rename from src/n1046_last_stone_weight.rs
rename to src/solution/s1046_last_stone_weight.rs

From 01ce862f8526b43ee73bd1c51df25bc4e4344947 Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Sun, 2 Feb 2020 18:33:22 +0800
Subject: [PATCH 2/9] fix

---
 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index e25be217..ccd0c491 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -116,7 +116,7 @@ fn generate_random_id(except_ids: &[u32]) -> u32 {
 }
 
 fn get_solved_ids() -> Vec<u32> {
-    let paths = fs::read_dir("./src").unwrap();
+    let paths = fs::read_dir("./src/problem").unwrap();
     let mut solved_ids = Vec::new();
 
     for path in paths {

From 360a3f47895a049679128b4c0b2c96e31e444f8c Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Sun, 2 Feb 2020 18:35:23 +0800
Subject: [PATCH 3/9] fix

---
 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index ccd0c491..3533f9d5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,7 +37,7 @@ fn main() {
                     .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
                 if solved_ids.contains(&id) {
                     println!(
-                        "The problem you chose is invalid (the problem may have been solved \
+                        "The problem you chose is invalid (the problem may have been downloaded \
                          or may have no rust version)."
                     );
                     continue;

From f90c44eef14a18986851d26af39ceccaad17718b Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Sun, 2 Feb 2020 18:36:04 +0800
Subject: [PATCH 4/9] fix

---
 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 3533f9d5..3501fe34 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,7 +37,7 @@ fn main() {
                     .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
                 if solved_ids.contains(&id) {
                     println!(
-                        "The problem you chose is invalid (the problem may have been downloaded \
+                        "The problem you chose is invalid (the problem may have been initialized \
                          or may have no rust version)."
                     );
                     continue;

From 9f05e1fb83c1ba3f6976f587ce617c225bf2eb5b Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Sun, 2 Feb 2020 20:37:35 +0800
Subject: [PATCH 5/9] add option to solve problem

---
 Cargo.lock  | 19 ++++++------
 Cargo.toml  |  1 +
 src/main.rs | 88 +++++++++++++++++++++++++++++++++++++++++------------
 3 files changed, 80 insertions(+), 28 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index d542a78d..69f4ab42 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -448,6 +448,7 @@ name = "leetcode-rust"
 version = "0.1.0"
 dependencies = [
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.9.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.101 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.101 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -681,7 +682,7 @@ dependencies = [
  "error-chain 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "idna 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -849,18 +850,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "regex"
-version = "1.3.1"
+version = "1.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.12"
+version = "0.6.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1071,7 +1072,7 @@ dependencies = [
 
 [[package]]
 name = "thread_local"
-version = "0.3.6"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1454,8 +1455,8 @@ dependencies = [
 "checksum rand_xorshift 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 "checksum redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)" = "2439c63f3f6139d1b57529d16bc3b8bb855230c8efcc5d3a896c8bea7c3b1e84"
-"checksum regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dc220bd33bdce8f093101afe22a037b8eb0e5af33592e6a9caafff0d4cb81cbd"
-"checksum regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)" = "11a7e20d1cce64ef2fed88b66d347f88bd9babb82845b2b858f3edbf59a4f716"
+"checksum regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "322cf97724bea3ee221b78fe25ac9c46114ebb51747ad5babd51a2fc6a8235a8"
+"checksum regex-syntax 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)" = "b28dfe3fe9badec5dbf0a79a9cccad2cfc2ab5484bdb3e44cbd1ae8b3ba2be06"
 "checksum remove_dir_all 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4a83fa3702a688b9359eccba92d153ac33fd2e8462f9e0e3fdf155239ea7792e"
 "checksum reqwest 0.9.21 (registry+https://github.com/rust-lang/crates.io-index)" = "02b7e953e14c6f3102b7e8d1f1ee3abf5ecee80b427f5565c9389835cecae95c"
 "checksum rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
@@ -1478,7 +1479,7 @@ dependencies = [
 "checksum syn 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "66850e97125af79138385e9b88339cbcd037e3f28ceab8c5ad98e64f0f1f80bf"
 "checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
-"checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
+"checksum thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
 "checksum time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)" = "db8dcfca086c1143c9270ac42a2bbd8a7ee477b78ac8e45b19abfb0cbede4b6f"
 "checksum tokio 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)" = "5a09c0b5bb588872ab2f09afa13ee6e9dac11e10a0ec9e8e3ba39a5a5d530af6"
 "checksum tokio-buf 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8fb220f46c53859a4b7ec083e41dec9778ff0b1851c0942b211edb89e0ccdc46"
diff --git a/Cargo.toml b/Cargo.toml
index c414242f..f6b7c1c5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ serde = "1.0"
 serde_json = "1.0"
 serde_derive = "1.0"
 rand = "0.6.5"
+regex = "1.3.4"
 
 [lib]
 doctest = false
diff --git a/src/main.rs b/src/main.rs
index 3501fe34..9c3fd6d7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,10 +5,12 @@ extern crate serde_json;
 
 mod fetcher;
 
+use regex::Regex;
 use std::env;
 use std::fs;
+use std::fs::File;
 use std::io;
-use std::io::Write;
+use std::io::{BufRead, Write};
 use std::path::Path;
 
 /// main() helps to generate the submission template .rs
@@ -18,30 +20,44 @@ fn main() {
     loop {
         println!("Please enter a frontend problem id, or \"random\" to generate a random one.");
         let mut is_random = false;
+        let mut is_solving = false;
         let mut id: u32 = 0;
         let mut id_arg = String::new();
         io::stdin()
             .read_line(&mut id_arg)
             .expect("Failed to read line");
         let id_arg = id_arg.trim();
-        match id_arg {
-            "random" => {
-                println!("You select random mode.");
-                id = generate_random_id(&solved_ids);
-                is_random = true;
-                println!("Generate random problem: {}", &id);
-            }
-            _ => {
-                id = id_arg
-                    .parse::<u32>()
-                    .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
-                if solved_ids.contains(&id) {
-                    println!(
-                        "The problem you chose is invalid (the problem may have been initialized \
-                         or may have no rust version)."
-                    );
-                    continue;
-                }
+
+        let random_pattern = Regex::new(r"^random$").unwrap();
+        let solving_pattern = Regex::new(r"^solve (\d+)$").unwrap();
+
+        if random_pattern.is_match(id_arg) {
+            println!("You select random mode.");
+            id = generate_random_id(&solved_ids);
+            is_random = true;
+            println!("Generate random problem: {}", &id);
+        } else if solving_pattern.is_match(id_arg) {
+            // solve a problem
+            // move it from problem/ to solution/
+            is_solving = true;
+            id = solving_pattern
+                .captures(id_arg)
+                .unwrap()
+                .get(1)
+                .unwrap()
+                .as_str()
+                .parse()
+                .unwrap();
+        } else {
+            id = id_arg
+                .parse::<u32>()
+                .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
+            if solved_ids.contains(&id) {
+                println!(
+                    "The problem you chose is invalid (the problem may have been initialized \
+                     or may have no rust version)."
+                );
+                continue;
             }
         }
 
@@ -66,6 +82,40 @@ fn main() {
             problem.title_slug.replace("-", "_")
         );
         let file_path = Path::new("./src/problem").join(format!("{}.rs", file_name));
+        if is_solving {
+            // check problem/ existence
+            if !file_path.exists() {
+                panic!("problem does not exist");
+            }
+            // check solution/ no existence
+            let solution_name = format!(
+                "s{:04}_{}",
+                problem.question_id,
+                problem.title_slug.replace("-", "_")
+            );
+            let solution_path = Path::new("./src/solution").join(format!("{}.rs", solution_name));
+            if solution_path.exists() {
+                panic!("solution exists");
+            }
+            // rename/move file
+            fs::rename(file_path, solution_path).unwrap();
+            // remove from problem/mod.rs
+            let mod_file = "./src/problem/mod.rs";
+            let target_line = format!("mod {};", file_name);
+            let lines: Vec<String> = io::BufReader::new(File::open(mod_file).unwrap())
+                .lines()
+                .map(|x| x.unwrap())
+                .filter(|x| *x != target_line)
+                .collect();
+            fs::write(mod_file, lines.join("\n"));
+            // insert into solution/mod.rs
+            let mut lib_file = fs::OpenOptions::new()
+                .append(true)
+                .open("./src/solution/mod.rs")
+                .unwrap();
+            writeln!(lib_file, "mod {};", solution_name);
+            break;
+        }
         if file_path.exists() {
             panic!("problem already initialized");
         }

From 0d72e628b6c6b11cc5edca9725e3d505fcc7c355 Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Tue, 4 Feb 2020 10:57:03 +0800
Subject: [PATCH 6/9] add a message to explain the solve $i command

---
 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 9c3fd6d7..f58192c0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -18,7 +18,7 @@ fn main() {
     println!("Welcome to leetcode-rust system.");
     let mut solved_ids = get_solved_ids();
     loop {
-        println!("Please enter a frontend problem id, or \"random\" to generate a random one.");
+        println!("Please enter a frontend problem id, or \"random\" to generate a random one, or \"solve $i\" to move problem to solution/");
         let mut is_random = false;
         let mut is_solving = false;
         let mut id: u32 = 0;

From 125c64c39b035d4cab2687d9bc2977749c8b0a59 Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Tue, 4 Feb 2020 11:06:16 +0800
Subject: [PATCH 7/9] clarify error message

---
 src/main.rs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index f58192c0..87c333fc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -53,10 +53,7 @@ fn main() {
                 .parse::<u32>()
                 .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
             if solved_ids.contains(&id) {
-                println!(
-                    "The problem you chose is invalid (the problem may have been initialized \
-                     or may have no rust version)."
-                );
+                println!("The problem you chose has been initialized in problem/");
                 continue;
             }
         }

From 76edb8c5fb172de61a1e308d279e9b877ad32c5f Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Tue, 4 Feb 2020 11:24:08 +0800
Subject: [PATCH 8/9] refactor get_solved_ids() according to current logic

---
 src/main.rs | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 87c333fc..545c2d22 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -163,20 +163,12 @@ fn generate_random_id(except_ids: &[u32]) -> u32 {
 }
 
 fn get_solved_ids() -> Vec<u32> {
-    let paths = fs::read_dir("./src/problem").unwrap();
-    let mut solved_ids = Vec::new();
-
-    for path in paths {
-        let path = path.unwrap().path();
-        let s = path.to_str().unwrap();
-        if !s.starts_with('n') {
-            continue;
-        }
-        let id = &s[7..11];
-        let id = id.parse::<u32>().unwrap();
-        solved_ids.push(id);
-    }
-    solved_ids
+    let content = fs::read_to_string("./src/problem/mod.rs").unwrap();
+    let id_pattern = Regex::new(r"p(\d{4})_").unwrap();
+    id_pattern
+        .captures_iter(&content)
+        .map(|x| x.get(1).unwrap().as_str().parse().unwrap())
+        .collect()
 }
 
 fn parse_extra_use(code: &str) -> String {

From 695f53a684264b19f0d2e94541fdb18cc1f37628 Mon Sep 17 00:00:00 2001
From: songyzh <mailsyzh@gmail.com>
Date: Tue, 4 Feb 2020 11:28:00 +0800
Subject: [PATCH 9/9] clarify var and fn name

---
 src/main.rs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 545c2d22..cf5d251b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,7 +16,7 @@ use std::path::Path;
 /// main() helps to generate the submission template .rs
 fn main() {
     println!("Welcome to leetcode-rust system.");
-    let mut solved_ids = get_solved_ids();
+    let mut initialized_ids = get_initialized_ids();
     loop {
         println!("Please enter a frontend problem id, or \"random\" to generate a random one, or \"solve $i\" to move problem to solution/");
         let mut is_random = false;
@@ -33,7 +33,7 @@ fn main() {
 
         if random_pattern.is_match(id_arg) {
             println!("You select random mode.");
-            id = generate_random_id(&solved_ids);
+            id = generate_random_id(&initialized_ids);
             is_random = true;
             println!("Generate random problem: {}", &id);
         } else if solving_pattern.is_match(id_arg) {
@@ -52,7 +52,7 @@ fn main() {
             id = id_arg
                 .parse::<u32>()
                 .unwrap_or_else(|_| panic!("not a number: {}", id_arg));
-            if solved_ids.contains(&id) {
+            if initialized_ids.contains(&id) {
                 println!("The problem you chose has been initialized in problem/");
                 continue;
             }
@@ -68,7 +68,7 @@ fn main() {
         let code = problem.code_definition.iter().find(|&d| d.value == "rust");
         if code.is_none() {
             println!("Problem {} has no rust version.", &id);
-            solved_ids.push(problem.question_id);
+            initialized_ids.push(problem.question_id);
             continue;
         }
         let code = code.unwrap();
@@ -162,7 +162,7 @@ fn generate_random_id(except_ids: &[u32]) -> u32 {
     }
 }
 
-fn get_solved_ids() -> Vec<u32> {
+fn get_initialized_ids() -> Vec<u32> {
     let content = fs::read_to_string("./src/problem/mod.rs").unwrap();
     let id_pattern = Regex::new(r"p(\d{4})_").unwrap();
     id_pattern