Esport used colorPP

#include<stdio.h>
#include<vector>
#include<stack>
using namespace std;
int const N = 100010;
int color[N];
vector<int> adj[N];

bool check(int u){
    if(color[u] == 2)return false;
    if(color[u] == 1)return true;
    color[u] = 1;
    bool ans = false;
    for(int i=0;i<adj[u].size() && !ans;i++){
        ans = check(adj[u][i]);
    }
    if(!ans) color[u] = 2;
    return ans;
}

int main()
{
    int n,m;
    scanf("%d %d",&n,&m);
    for(int i=0;i<m;i++){
        int u,v;
        scanf("%d %d",&u,&v);
        adj[u].push_back(v);
    }
    bool ans = false;
    for(int i=1;i<=n && !ans;i++){
        ans = check(i);
    }
    printf("%s",(ans ? "Yes" : "No"));

}