dataStructure@ Check if a directed graph has cycles

#include<iostream>
#include<cstdio>
#include<cstring>
#include<limits>
#include<vector>
using namespace std;
const int maxn = 10;
struct edge{
    int to, cost;
    edge(int t){
        this->to = t; this->cost = 0;
    }
};
void addEdge(vector<edge> &edgelist, vector<vector<int> > &G, int from, int to){
    edgelist.push_back(edge(to));
    G[from].push_back(edgelist.size()-1);
}
void addDoubleEdge(vector<edge> &edgelist, vector<vector<int> > &G, int from, int to){
    addEdge(edgelist,G,from,to);
    addEdge(edgelist,G,to,from);
}
bool isCyclic(vector<edge> edgelist, vector<vector<int> > G,vector<bool> vis, vector<bool> RecStack, int v){
    for(int i=0;i<G[v].size();++i){
        edge e = edgelist[G[v][i]];
        if(RecStack[e.to]) return true;
        if(!vis[e.to]){
            vis[e.to] = true; RecStack[e.to] = true;
            if(isCyclic(edgelist,G,vis,RecStack,e.to)) return true;
            RecStack[e.to] = false;
        }
    }
    return false;
}
void buildMap(vector<edge> &edgelist, vector<vector<int> > &G){
    addEdge(edgelist,G,0,1);
    addEdge(edgelist,G,0,2);
    addEdge(edgelist,G,2,0);
    addEdge(edgelist,G,1,2);
    addEdge(edgelist,G,2,3);
    addEdge(edgelist,G,3,3);
}
int main(){
    vector<edge> edgelist;
    vector<vector<int> > G(maxn);
    vector<bool> vis(maxn);
    vector<bool> RecStack(maxn);
    
    buildMap(edgelist,G);
    
    for(int i=0;i<vis.size();++i) vis[i]=false;
    for(int i=0;i<RecStack.size();++i) RecStack[i]=false;
    
    for(int i=0;i<G.size();++i){
        if(!vis[i]){
            vis[i] = true; RecStack[i] = true;
            if(isCyclic(edgelist,G,vis,RecStack,i)){
                cout<<i<<" starts a cycle"<<endl; 
            }
            RecStack[i] = false;
        }
    }
    
    return 0;
}