trinagle partition

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int t;
    cin>>t;
    while(t--){
    int a,b,n;
    cin>>n;

vector< pair < pair<int,int>,int> >sura;
for(int i=0;i<3*n;i++)
{
    cin>>a>>b;
    sura.push_back( make_pair(make_pair(a,b),i));
}
sort(sura.begin(),sura.end());
for(int i=0;i<n;i++)
{
   cout<<sura[3*i].second+1<<" "<<sura[3*i+1].second+1<<" "<<sura[3*i+2].second+1<<endl;
}

    }


}