Cycle Detection in directed graph using DFS (Implementation in STL Cpp)

Program:-

#include <bits/stdc++.h>
using namespace std;
int cycle=0;
void dfs(vector<int>*vec,vector<bool>&vis,int index,vector<bool>&visited){
    if(vis[index]==true) return;
    vis[index]=true;
    visited[index]=true;
    //cout<<index<<" ";
    for(int i=0;i<vec[index].size();i++){
        if(visited[vec[index][i]]) cycle=1;
        if(vis[vec[index][i]]==false){
            dfs(vec,vis,vec[index][i],visited);
        }
       
    }
}

int main() {
    int n,m;
    cin>>n>>m;
    vector<int>vec[n];
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        vec[a].push_back(b);
    }
    vector<bool>vis(n,false);
    for(int i=0;i<n;i++){
        if(vis[i]==false){
            vector<bool>visited(n,false);
            dfs(vec,vis,i,visited);
        }
    }
    if(cycle) cout<<"Cycle";
    else cout<<"Not Cycle";
    return 0;
}