Update index.ts

Author: masx200

number-of-closed-islands/index.ts

@@ -1,2 +1,31 @@
-function closedIsland(grid: number[][]): number {}
+function closedIsland(grid: number[][]): number {
+    const m = grid.length;
+    const n = grid[0].length;
+    let res = 0;
+    grid.forEach((a, i) =>
+        a.forEach((v, j) => {
+            if (v === 0) {
+                res += Number(dfs(i, j));
+            }
+        })
+    );
+    function dfs(i: number, j: number): boolean {
+        if (i < 0 || j < 0 || i >= m || j >= n) {
+            return false;
+        }
+        if (grid[i][j]) return true;
+        grid[i][j] = 1;
+
+        return [
+            [i - 1, j],
+            [i, j + 1],
+            [i + 1, j],
+            [i, j - 1],
+        ]
+            .map((v) => dfs(v[0], v[1]))
+            .reduce((a, v) => a && v);
+    }
+
+    return res;
+}
 export default closedIsland;