word search solution

Author: hyer0705

word-search/hyer0705.ts

@@ -0,0 +1,48 @@
+function exist(board: string[][], word: string): boolean {
+  const m = board.length;
+  const n = board[0].length;
+
+  const visited: boolean[][] = Array.from({ length: m }, () => Array(n).fill(false));
+
+  const isValidCoordinates = (index: number, x: number, y: number): boolean => {
+    if (x >= 0 && x < m && y >= 0 && y < n && word[index] === board[x][y] && !visited[x][y]) return true;
+    return false;
+  };
+
+  const backtrack = (index: number, cx: number, cy: number): boolean => {
+    if (index === word.length - 1 && board[cx][cy] === word[index]) return true;
+
+    if (board[cx][cy] !== word[index]) return false;
+
+    for (const [dx, dy] of [
+      [0, 1],
+      [0, -1],
+      [1, 0],
+      [-1, 0],
+    ]) {
+      const [nx, ny] = [cx + dx, cy + dy];
+
+      if (isValidCoordinates(index + 1, nx, ny)) {
+        visited[nx][ny] = true;
+        const result = backtrack(index + 1, nx, ny);
+        if (result) return true;
+        visited[nx][ny] = false;
+      }
+    }
+
+    return false;
+  };
+
+  for (let i = 0; i < m; i++) {
+    for (let j = 0; j < n; j++) {
+      if (board[i][j] === word[0]) {
+        visited[i][j] = true;
+        const result: boolean = backtrack(0, i, j);
+        if (result) return true;
+        visited[i][j] = false;
+      }
+    }
+  }
+
+  return false;
+}