Update 0200-number-of-islands.ts

typescript/0200-number-of-islands.ts

@@ -1,54 +1,29 @@
-//BFS way to solve this
-const bfs = (grid, r, c) => {
-    const [ROWS, COLS] = [grid.length, grid[0].length];
-
-    const directions = [
-        [-1, 0],
-        [1, 0],
-        [0, -1],
-        [0, 1],
-    ];
-
-    let queue = [[r, c]];
-
-    //marks as visited
-    grid[r][c] = '0';
-
-    while (queue.length > 0) {
-        //dequeues the first element(current)
-        let [cr, cc] = queue.shift();
-
-        directions.forEach(([dr, dc]) => {
-            let [nr, nc] = [cr + dr, cc + dc];
-            if (
-                !(
-                    nr < 0 ||
-                    nc < 0 ||
-                    nr >= ROWS ||
-                    nc >= COLS ||
-                    grid[nr][nc] === '0'
-                )
-            ) {
-                queue.push([nr, nc]);
-                grid[nr][nc] = '0';
-            }
-        });
+const dfs = (grid: string[][], i: number, j: number) => {
+    if (
+        i < 0 ||
+        j < 0 ||
+        i >= grid.length ||
+        j >= grid[0].length ||
+        grid[i][j] == '0'
+    ) {
+        return;
     }
+    grid[i][j] = '0';
+    dfs(grid, i + 1, j);
+    dfs(grid, i, j + 1);
+    dfs(grid, i - 1, j);
+    dfs(grid, i, j - 1);
 };
 
 function numIslands(grid: string[][]): number {
-    const [ROWS, COLS] = [grid.length, grid[0].length];
-
-    let islands = 0;
-
-    for (let i = 0; i < ROWS; i++) {
-        for (let j = 0; j < COLS; j++) {
-            if (grid[i][j] === '1') {
-                bfs(grid, i, j);
-                islands++;
+    let count: number = 0;
+    for (let i = 0; i < grid.length; i++) {
+        for (let j = 0; j < grid[0].length; j++) {
+            if (grid[i][j] == '1') {
+                dfs(grid, i, j);
+                count++;
             }
         }
     }
-
-    return islands;
+    return count;
 }