Solved 0322

Author: guangsheng.li01

src/a0322_coin_change.rs

@@ -0,0 +1,55 @@
+/*
+ * [0322] coin-change
+ */
+
+pub struct Solution {}
+
+use std::cmp::min;
+use std::collections::HashMap;
+use std::i32::MAX;
+impl Solution {
+    pub fn coin_change(coins: Vec<i32>, amount: i32) -> i32 {
+        if amount == 0 {
+            return 0;
+        }
+        let mut dp: HashMap<i32, i32> = HashMap::new();
+        Self::dfs(&coins, amount, &mut dp)
+    }
+
+    fn dfs(coins: &Vec<i32>, amount: i32, dp: &mut HashMap<i32, i32>) -> i32 {
+        if amount <= 0 {
+            return -1;
+        }
+        if let Some(r) = dp.get(&amount) {
+            return *r;
+        }
+
+        for i in coins {
+            if *i == amount {
+                return 1;
+            }
+        }
+
+        let mut result = MAX;
+        for i in (0..coins.len()).rev() {
+            let j = Self::dfs(coins, amount - coins[coins.len() - i - 1], dp);
+            if j != -1 {
+                result = min(result, j + 1)
+            }
+        }
+        result = if result == MAX { -1 } else { result };
+        dp.insert(amount, result);
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_case0() {
+        assert_eq!(Solution::coin_change(vec![1, 2, 5], 11), 3);
+        assert_eq!(Solution::coin_change(vec![2], 3), -1);
+    }
+}

src/lib.rs

@@ -20,6 +20,7 @@ mod a0118_pascals_triangle;
 mod a0119_pascals_triangle_ii;
 mod a0145_binary_tree_postorder_traversal;
 mod a0172_factorial_trailing_zeroes;
+mod a0322_coin_change;
 mod a0392_is_subsequence;
 mod a0400_nth_digit;
 mod a0404_sum_of_left_leaves;