dfs走迷宫

public class Solution {
boolean flag= false;
// 行走路径
int[] x_visit = {0,1,0,-1};
int[] y_visit ={-1,0,1,0};
int visit[][];

    public boolean exist(char[][] board, String word) {
       
        int width= board.length;
        int height = board[0].length;
        visit = new int [width][height];
        for (int i = 0; i <width ; i++) {
            for (int j = 0; j < height; j++) {
                visit[i][j] = 0;
            }
        }
        char[] word_array = word.toCharArray();
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < height  ; j++) {
                if (flag){
                    return  flag;
                }
                dfs(board,word_array,i,j,0);
            }
        }
        return flag;
    }
    
    public void dfs (char[][] board, char[] word,int i,int j,int k){
        visit[i][j] = 1;
        if (board[i][j] != word[k]){
            return;
        }
        if (k == word.length-1 ){
            flag = true;
            return;
        }
        for (int l = 0; l < 4; l++) {
             
            if ((i+x_visit[l])>=0 && (i +x_visit[l])<4 && (j+y_visit[l])<4&& (j+y_visit[l])>=0 && visit[i][j]==0){
                dfs(board,word,i +x_visit[l],j+y_visit[l],k+1);
                visit[i +x_visit[l]][j+y_visit[l]] =0;
            }
        }
        visit[i][j] = 0;
        
        return;
        
    }

}