79_word_search.js

/**
 * @param {character[][]} board
 * @param {string} word
 * @return {boolean}
 */
var exist = function (board, word) {
    const m = board.length;
    const n = board[0].length;
  
    // Helper function to perform DFS search
    function dfs(i, j, index) {
      if (index === word.length) return true;
      if (i < 0 || j < 0 || i >= m || j >= n || board[i][j] !== word[index])
        return false;
  
      const temp = board[i][j]; // Temporarily mark current cell as visited
      board[i][j] = "#"; // Mark visited
  
      // Explore adjacent cells
      const found =
        dfs(i + 1, j, index + 1) ||
        dfs(i - 1, j, index + 1) ||
        dfs(i, j + 1, index + 1) ||
        dfs(i, j - 1, index + 1);
  
      board[i][j] = temp; // Restore cell
  
      return found;
    }
  
    // Iterate through each cell in the board
    for (let i = 0; i < m; i++) {
      for (let j = 0; j < n; j++) {
        if (dfs(i, j, 0)) return true; // If word found, return true
      }
    }
  
    return false; // Word not found
  };