Number of island

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

Author: begeekmyfriend

002_add_two_numbers/add_two_numbers.c

@@ -8,7 +8,8 @@ struct ListNode {
     struct ListNode *next;
 };
 
-struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
+static struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2)
+{
     int carry_num = 0;
     int first = 1;
     struct ListNode *res = NULL;
@@ -90,6 +91,11 @@ static void show(struct ListNode *ln)
 
 int main(int argc, char **argv)
 {
+    if (argc < 3) {
+        fprintf(stderr, "Usage: ./test n1 n2\n");
+        exit(-1);
+    }
+
     struct ListNode *l1 = node_build(argv[1]);
     struct ListNode *l2 = node_build(argv[2]);
     struct ListNode *res = addTwoNumbers(l1, l2);

200_number_of_islands/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test islands.c

200_number_of_islands/islands.c

@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void recursive(char** grid, int row_size, int col_size, int row, int col)
+{
+    grid[row][col] = '0';
+
+    if (row > 0 && grid[row - 1][col] == '1') {
+        recursive(grid, row_size, col_size, row - 1, col);
+    }
+
+    if (row < row_size - 1 && grid[row + 1][col] == '1') {
+        recursive(grid, row_size, col_size, row + 1, col);
+    }
+
+    if (col > 0 && grid[row][col - 1] == '1') {
+        recursive(grid, row_size, col_size, row, col - 1);
+    }
+
+    if (col < col_size - 1 && grid[row][col + 1] == '1') {
+        recursive(grid, row_size, col_size, row, col + 1);
+    }
+}
+
+static int numIslands(char** grid, int gridRowSize, int gridColSize)
+{
+    int i, j, count = 0;
+    for (i = 0; i < gridRowSize; i++) {
+        for (j = 0; j < gridColSize; j++) {
+            if (grid[i][j] == '1') {
+                recursive(grid, gridRowSize, gridColSize, i, j);
+                count++;
+            }
+        }
+    }
+
+    return count;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test 11000 11000 00100 00011\n");
+        exit(-1);
+    }
+
+    int i, j;
+    int row_size = argc - 1;
+    int col_size = strlen(argv[1]);
+    char **grid = malloc(row_size * sizeof(char *));
+    for (i = 0; i < row_size; i++) {
+            grid[i] = malloc(col_size);
+            memcpy(grid[i], argv[i + 1], col_size);
+    }
+
+    printf("%d\n", numIslands(grid, row_size, col_size));
+    return 0;
+}