还是有1、5、7三个点WA,求指点

#include<stdio.h>
#include <algorithm>
using namespace std;
#define MAX 105

int f[MAX][MAX], dp[MAX][MAX],n = 0, m = 0,sum=0;
int X[] = { 0,0,-1,1};
int Y[] = { 1,-1,0,0};
//判断坐标x，y是否需要被访问
bool judge(int x,int y) {
    if (x > n || x<1 || y>m || y < 1)//越界是否
        return false;
    return true;
}
int DFS(int x, int y) {
    int num = 0,tempx=-1,tempy=-1,t1=0,t2=0;
    if (dp[x][y]!=0)
    {
        return dp[x][y];
    }
    for (int k = 0; k < 4; k++)
    {
        tempx = x + X[k];
        tempy = y + Y[k];
        if (judge(tempx,tempy)&&f[tempx][tempy] < f[x][y]&& f[tempx][tempy]>num)
        {
            num = f[tempx][tempy];
            t1 = tempx;
            t2 = tempy;
        }
    }

    if (num!=0)
        return DFS(t1, t2)+1;
    else
        return 1;
}

int main() {

    int flag = 0;
    scanf("%d%d", &n,&m);
    for (int i = 1; i <= n; i++){//赋值给二维数组
        for (int j = 1; j <=m; j++)
            scanf("%d", &f[i][j]);
        }
    for (int i = 1; i <= n; i++) 
        for (int j = 1;j <= m;j++) {
                if (dp[i][j] == 0) 
                dp[i][j] = DFS(i, j);
            sum = max(sum, dp[i][j]);    
        }

    printf("%d", sum);
}