fix: fix typescript solution to lc problem: No.0200.Number of Islands (doocs#476)

Author: zhaocchen

solution/0200-0299/0200.Number of Islands/README.md

@@ -83,27 +83,23 @@ function numIslands(grid: string[][]): number {
     for (let i = 0; i < m; ++i) {
         for (let j = 0; j < n; ++j) {
             if (grid[i][j] == '1') {
-                bfs(grid, i, j)
+                dfs(grid, i, j);
                 ++ans;
             }
         }
     }
     return ans;
 };
 
-function bfs(grid: string[][], r: number, c: number): void {
+function dfs(grid: string[][], i: number, j: number) {
     let m = grid.length, n = grid[0].length;
-    let queue = new Array();
-    queue.push([r, c]);
-    while (queue.length > 0) {
-        let [i, j] = queue.shift();
-        for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
-            let x = i + dx, y = j + dy;
-            if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] == '1') {
-                grid[x][y] = '0';
-                queue.push([x, y]);
-            }
-        }
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || grid[i][j] == '0') {
+        return;
+    }
+    grid[i][j] = '0';
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        dfs(grid, x, y);
     }
 }
 ```

solution/0200-0299/0200.Number of Islands/README_EN.md

@@ -69,27 +69,23 @@ function numIslands(grid: string[][]): number {
     for (let i = 0; i < m; ++i) {
         for (let j = 0; j < n; ++j) {
             if (grid[i][j] == '1') {
-                bfs(grid, i, j)
+                dfs(grid, i, j);
                 ++ans;
             }
         }
     }
     return ans;
 };
 
-function bfs(grid: string[][], r: number, c: number): void {
+function dfs(grid: string[][], i: number, j: number) {
     let m = grid.length, n = grid[0].length;
-    let queue = new Array();
-    queue.push([r, c]);
-    while (queue.length > 0) {
-        let [i, j] = queue.shift();
-        for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
-            let x = i + dx, y = j + dy;
-            if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] == '1') {
-                grid[x][y] = '0';
-                queue.push([x, y]);
-            }
-        }
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || grid[i][j] == '0') {
+        return;
+    }
+    grid[i][j] = '0';
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        dfs(grid, x, y);
     }
 }
 ```

solution/0200-0299/0200.Number of Islands/Solution.ts

@@ -4,26 +4,22 @@ function numIslands(grid: string[][]): number {
     for (let i = 0; i < m; ++i) {
         for (let j = 0; j < n; ++j) {
             if (grid[i][j] == '1') {
-                bfs(grid, i, j)
+                dfs(grid, i, j);
                 ++ans;
             }
         }
     }
     return ans;
 };
 
-function bfs(grid: string[][], r: number, c: number): void {
+function dfs(grid: string[][], i: number, j: number) {
     let m = grid.length, n = grid[0].length;
-    let queue = new Array();
-    queue.push([r, c]);
-    while (queue.length > 0) {
-        let [i, j] = queue.shift();
-        for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
-            let x = i + dx, y = j + dy;
-            if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] == '1') {
-                grid[x][y] = '0';
-                queue.push([x, y]);
-            }
-        }
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || grid[i][j] == '0') {
+        return;
+    }
+    grid[i][j] = '0';
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        dfs(grid, x, y);
     }
 }