feat: add typescript solution to lc problem: No.0079.Word Search (doocs#474)

Author: zhaocchen

solution/0000-0099/0079.Word Search/README.md

@@ -54,7 +54,7 @@
 
 <!-- 这里可写通用的实现逻辑 -->
 
-深度优先搜索 DFS 实现。
+回溯（深度优先搜索 DFS ）实现。
 
 <!-- tabs:start -->
 
@@ -122,6 +122,47 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function exist(board: string[][], word: string): boolean {
+    let m = board.length, n = board[0].length;
+    let visited = Array.from({ length: m }, v => new Array(n).fill(false));
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            if (dfs(board, word, i, j, 0, visited)) {
+                return true;
+            }
+        }
+    }
+    return false;
+};
+
+function dfs(board: string[][], word: string, i: number, j: number, depth: number, visited: boolean[][]): boolean {
+    let m = board.length, n = board[0].length;
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || visited[i][j]) {
+        return false;
+    }
+    if (board[i][j] != word.charAt(depth)) {
+        return false;
+    }
+
+    if (depth == word.length - 1) {
+        return true;
+    }
+
+    visited[i][j] = true;
+    ++depth;
+    let res = false;
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        res = res || dfs(board, word, x, y, depth, visited);
+    }
+    visited[i][j] = false;
+    return res;
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0079.Word Search/README_EN.md

@@ -109,6 +109,47 @@ class Solution {
 }
 ```
 
+### **TypeScript**
+
+```ts
+function exist(board: string[][], word: string): boolean {
+    let m = board.length, n = board[0].length;
+    let visited = Array.from({ length: m }, v => new Array(n).fill(false));
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            if (dfs(board, word, i, j, 0, visited)) {
+                return true;
+            }
+        }
+    }
+    return false;
+};
+
+function dfs(board: string[][], word: string, i: number, j: number, depth: number, visited: boolean[][]): boolean {
+    let m = board.length, n = board[0].length;
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || visited[i][j]) {
+        return false;
+    }
+    if (board[i][j] != word.charAt(depth)) {
+        return false;
+    }
+
+    if (depth == word.length - 1) {
+        return true;
+    }
+
+    visited[i][j] = true;
+    ++depth;
+    let res = false;
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        res = res || dfs(board, word, x, y, depth, visited);
+    }
+    visited[i][j] = false;
+    return res;
+}
+```
+
 ### **...**
 
 ```

solution/0000-0099/0079.Word Search/Solution.ts

@@ -0,0 +1,36 @@
+function exist(board: string[][], word: string): boolean {
+    let m = board.length, n = board[0].length;
+    let visited = Array.from({ length: m }, v => new Array(n).fill(false));
+    for (let i = 0; i < m; ++i) {
+        for (let j = 0; j < n; ++j) {
+            if (dfs(board, word, i, j, 0, visited)) {
+                return true;
+            }
+        }
+    }
+    return false;
+};
+
+function dfs(board: string[][], word: string, i: number, j: number, depth: number, visited: boolean[][]): boolean {
+    let m = board.length, n = board[0].length;
+    if (i < 0 || i > m - 1 || j < 0 || j > n - 1 || visited[i][j]) {
+        return false;
+    }
+    if (board[i][j] != word.charAt(depth)) {
+        return false;
+    }
+
+    if (depth == word.length - 1) {
+        return true;
+    }
+
+    visited[i][j] = true;
+    ++depth;
+    let res = false;
+    for (let [dx, dy] of [[0, 1], [0, -1], [1, 0], [-1, 0]]) {
+        let x = i + dx, y = j + dy;
+        res = res || dfs(board, word, x, y, depth, visited);
+    }
+    visited[i][j] = false;
+    return res;
+}