leetcode 剑指 Offer 12. 矩阵中的路径

0.code

class Solution {
    public boolean exist(char[][] board, String word) {
        if(board==null||board.length==0||board[0].length==0){
            return false;
        }
        int row=board.length;
        int col = board[0].length;
        int[][] visit = new int[row][col];
        for(int i=0;i<row;i++){
            for(int j=0;j<col;j++){
                visit[i][j] = 0;
            }
        }
        for(int i=0;i<row;i++){
            for(int j=0;j<col;j++){
                if(existHelp(board,i,j,visit,word,0)){
                    return true;
                }
            }
        }
        return false;
    }
    public boolean existHelp(char[][] board,int i,int j, int[][]visit, String word,int index){
        if(index>=word.length()){
            return true;
        } 
        if(i<0||i>=board.length||j<0||j>=board[0].length){
            return false;
        }
        if(board[i][j]==word.charAt(index)&&visit[i][j]==0){
            visit[i][j] = 1;
            if(existHelp(board,i-1,j,visit,word,index+1)||existHelp(board,i+1,j,visit,word,index+1)||existHelp(board,i,j-1,visit,word,index+1)||existHelp(board,i,j+1,visit,word,index+1)){
                return true;
            }
            visit[i][j] = 0;
            return false;
        }else{
            return false;
        }
    }

}