20pts求调 用出度入度做的 WA8个

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,m;
    short int l[5005][5005]={0};
    int in[5005]={0},out[5005]={0},ans[5005]={0},answer=0,lef=0;
    scanf("%d %d",&n,&m);
    for(int i=1;i<=m;i++){
        int a,b;
        scanf("%d %d",&a,&b);
        out[a]++;in[b]++;
        l[a][b]=1;
    }
    for(int i=1;i<=n;i++){
        if(out[i]==0&&in[i]!=0){
            lef++;
        }
        if(in[i]==0&&out[i]!=0){
            ans[i]++;
        }
    }
    int ni=n;
    while(ni-lef!=0){
        for(int i=1;i<=n;i++){
            if(in[i]==0&&out[i]!=0){
                for(int j=1;j<=n;j++){
                    if(l[i][j]!=0){
                        in[j]--;
                        ans[j]+=ans[i];
                    }
                }
                ni--;
                in[i]--;
            }
        }
    }
    for(int i=1;i<=n;i++){
        if(out[i]==0){
            answer=(answer+ans[i])%80112002;
        }
    }
    cout<<answer;
}