79.md

#79. Word Search 题目链接

public class Solution {
    public boolean exist(char[][] board, String word) {
        char[] words = word.toCharArray();
        // 遍历每一个点作为起点
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[0].length; j++) {
                if (exist(board, words, i, j, 0)) {
                    return true;
                }
            }
        }
        return false;
    }

    public boolean exist(char[][] borad, char[] words, int x, int y, int i) {

        if (i == words.length) {
            return true;
        }

        if (x < 0 || y < 0 || x >= borad.length || y >= borad[0].length) {
            return false;
        }


        if (borad[x][y] != words[i]) {
            return false;
        }
        
        // 设置已访问
        borad[x][y] ^= 255;
        i++;
        // 递归查找邻接点
        boolean flag = exist(borad, words, x+1, y, i) || exist(borad, words, x-1, y, i)
                    || exist(borad, words, x, y+1, i) || exist(borad, words, x, y-1, i);
        // 恢复原值
        borad[x][y] ^= 255;
        return flag;
    }
}