求助，全WA，但是感觉没问题

代码如下，感谢！

#include<bits/stdc++.h>
#define FAST ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
using namespace std;

int a[105][105];
int ans[105][105];
int r,c;

int dfs(int row,int list){
    if(ans[row][list]!= -1){
        return ans[row][list];
    }
    int now=a[row][list];
    int up,down,left,right;
    if(row - 1>=1){
        if(a[row - 1][list]<now){
            up=dfs(row - 1,list);
        }
    }
    if(row + 1<=r){
        if(a[row + 1][list]<now){
            down=dfs(row + 1,list);
        }
    }
    if(list - 1>= 1){
        if(a[row][list - 1]<now){
            left=dfs(row,list - 1);
        }
    }
    if(list + 1<=c){
        if(a[row][list + 1]<now){
            right=dfs(row,list + 1);
        }
    }
    int anss=max(left,right);
    anss = max(anss, up);
    anss = max(anss, down);
    ans[row][list] = anss + 1;
    return ans[row][list];
}

int main(){
    FAST;
    int answer;
    cin >> r >> c;
    for(int i=1;i<=r;i++){
        for(int j=1;j<=c;j++){
            cin >> a[i][j];
            ans[i][j] = -1;
        }
    }
    for(int i=1;i<=r;i++){
        for(int j=1;j<=c;j++){
            answer = max(dfs(i,j),answer);

        }
    }
    cout << answer << endl;
    return 0;
}