Leetcode•Sep 27, 2025

Word Search

Hazrat Ali

Leetcode

The word can be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring. The same letter cell may not be used more than once.

 

Example 1:

Input: board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCCED"
Output: true

Example 2:

Input: board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "SEE"
Output: true

Example 3:

Input: board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCB"
Output: false


Solution
/**
 * @param {character[][]} board
 * @param {string} word
 * @return {boolean}
 */
const exist = (board, word) => {
  const m = board.length;
  const n = board[0].length;
  const di = [-1, 1, 0, 0];
  const dj = [0, 0, -1, 1];

  const backtracking = (row, col, index) => {
    if (index === word.length) {
      return true;
    }

    if (row < 0 || col < 0 || row >= m || col >= n) {
      return false;
    }

    if (board[row][col] !== word[index]) {
      return false;
    }

    const c = board[row][col];

    board[row][col] = '';

    for (let k = 0; k < 4; k++) {
      if (backtracking(row + di[k], col + dj[k], index + 1)) {
        return true;
      }
    }

    board[row][col] = c;

    return false;
  };

  for (let i = 0; i < m; i++) {
    for (let j = 0; j < n; j++) {
      if (backtracking(i, j, 0)) {
        return true;
      }
    }
  }

  return false;
};




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