最长递增路径

import java.util.*;


public class Solution {
    
    
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     * 递增路径的最大长度
     * @param matrix int整型二维数组 描述矩阵的每个数
     * @return int整型
     */
    public int maxLength;
    public int solve (int[][] matrix) {
    
    
        // write code here
        int[][] visited = new int[matrix.length][matrix[0].length];
        for(int i=0; i<matrix.length;i++){
    
    
            for(int j=0;j<matrix[0].length;j++){
    
    
                dfs(matrix, visited, i, j, 0, -1);
            }
        }
        return maxLength;
    }
    public void dfs(int[][] matrix, int[][] visited, int i, int j, int pathLength, int pre){
    
    
        if(i<0||i>=matrix.length||j<0||j>=matrix[0].length||visited[i][j]==1||matrix[i][j]<=pre){
    
    
             maxLength = Math.max(maxLength, pathLength);
             return;
        }
        visited[i][j]=1;
        dfs(matrix, visited, i-1, j, pathLength+1, matrix[i][j]);
        dfs(matrix, visited, i+1, j, pathLength+1, matrix[i][j]);
        dfs(matrix, visited, i, j-1, pathLength+1, matrix[i][j]);
        dfs(matrix, visited, i, j+1, pathLength+1, matrix[i][j]);
        visited[i][j]=0;
    }
}