Detect a cycle in Undirected Graph.cpp

#include <bits/stdc++.h>
using namespace std;
class Solution
{
public:
    bool checkForCycle(int s, int V, vector<int> adj[], vector<int> &visited)
    {
        
        queue<pair<int, int>> q;
        visited[s] = true;
        q.push({s, -1});
        while (!q.empty())
        {
            int node = q.front().first;
            int par = q.front().second;
            q.pop();
 
            for (auto it : adj[node])
            {
                if (!visited[it])
                {
                    visited[it] = true;
                    q.push({it, node});
                }
                else if (par != it)
                    return true;
            }
        }
        return false;
    }
    bool isCycle(int V, vector<int> adj[])
    {
        vector<int> vis(V - 1, 0);
        for (int i = 1; i <= V; i++)
        {
            if (!vis[i])
            {
                if (checkForCycle(i, V, adj, vis))
                    return true;
            }
        }
    }
};
 
void addEdge(vector<int> adj[],int u,int v)
{
    adj[u].push_back(v);
    adj[v].push_back(u);
}
int main()
{
    vector<int> adj[5];
   
    addEdge(adj,0,1);
    addEdge(adj,0,2);
    addEdge(adj,2,3);
    addEdge(adj,1,3);
    addEdge(adj,2,4);
   
    Solution obj;
    int num=obj.isCycle(5, adj);
    if(num==1)
    cout<<"Yes"<<endl;
    else
    cout<<"No"<<endl;
 
    return 0;
}