Update 0200.岛屿数量.深搜版.md 新增TS深度搜索优先解法

problems/0200.岛屿数量.深搜版.md

@@ -346,6 +346,46 @@ var numIslands = function (grid) {
 };
 ```
 
+### TypeScript
+
+```TypeScript
+function numIslands(grid: string[][]): number {
+	// 四个方向
+	const dir: number[][] = [[0, 1], [1, 0], [-1, 0], [0, -1]];
+	const [m, n]: [number, number] = [grid.length, grid[0].length];
+
+	function dfs(grid: string[][], visited: boolean[][], x: number, y: number) {
+		for (let i = 0; i < 4; i++) {
+			let nextX: number = x + dir[i][0];
+			let nextY: number = y + dir[i][1];
+			// 越界了，直接跳过
+			if (nextX < 0 || nextX >= m || nextY < 0 || nextY >= n) {
+				continue;
+			}
+			// 没有访问过同时是陆地
+			if (!visited[nextX][nextY] && grid[nextX][nextY] === '1') {
+				visited[nextX][nextY] = true;
+				dfs(grid, visited, nextX, nextY);
+			}
+		}
+	}
+
+	const visited: boolean[][] = Array.from({ length: m }, _ => new Array(n).fill(false));
+
+	let result: number = 0;
+	for (let i = 0; i < m; i++) {
+		for (let k = 0; k < n; k++) {
+			if (!visited[i][k] && grid[i][k] === '1') {
+				++result; // 遇到没访问过的陆地，+1
+				visited[i][k] = true;
+				dfs(grid, visited, i, k); // 将与其链接的陆地都标记上 true
+			}
+		}
+	}
+	return result;
+}
+```
+
 ### Go
 
 ```go