Array_operation/Connected-Components-Graphs.cpp at main · Ramasuper88/Array_operation · GitHub

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#include<bits/stdc++.h>
using namespace std;
vector<bool> vis;
int n,m;
vector<vector<int>> adj;
vector<int> components;

int get_comp(int idx)
{
    if(vis[idx])
    {
        return 0;
    }
    vis[idx]=true;
    int ans=1;
    for(auto i : adj[idx])
    {
        if(!vis[i])
        {
            ans+=get_comp(i);
            vis[i]=true;
        }
    }
    return ans;
}
int main()
{
    cin>>n>>m;
    adj = vector<vector<int>>(n);
    vis = vector<bool>(n,0);
    for(int i=0;i<m;i++)
    {
        int u,v;
        cin>>u>>v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for(int i=0;i<n;i++)
    {
        if(!vis[i])
        {
            components.push_back(get_comp(i));

        }
    }
    for(auto i : components)
    {
        cout<<i<<" ";
    }

    // choosing friend pair from other group

    long long ans=0;
    for(auto i : components)
    {
      ans+=i*(n-i);
    }
    //overcounting ko hatane ke liye
    // 2 3
    // 3 2 both are counted so divided by 2
    cout<<"\n"<<(ans)/2;

    return 0;
}