【每日一题】- 2019-08-07 - 79. 单词搜索 about leetcode HOT 4 CLOSED

/**
 * @param {character[][]} board
 * @param {string} word
 * @return {boolean}
 */
var exist = function (board, word) {
    var visited = Array.from({
        length: board.length
    }, () => new Array(board.length).fill(false));

    for (var i = 0; i < board.length; i++) {
        for (var j = 0; j < board[i].length; j++) {
            if (board[i][j] == word[0]) {
                if (temp(i, j, 0)) {
                    return true;
                }
            }
        }
    }
    return false;

    function temp(x, y, index) {
        if (x < 0 || y < 0 || x >= board.length || y >= board[0].length) return false;
        if (visited[x][y]) return false;
        if (index == word.length - 1 && board[x][y] == word[index]) return true;
        if (board[x][y] != word[index]) return false;

        visited[x][y] = true;
        var rel = temp(x - 1, y, index + 1) || temp(x + 1, y, index + 1) || temp(x, y - 1, index + 1) || temp(x, y + 1, index + 1);
        if (rel) return true;
        visited[x][y] = false;
        return false;
    }
};