Pairs

Using Vectors

#include<vector>

#include<bits/stdc++.h>

 using namespace std;

  int main()

  {

      int n,i,a;

      cin>>n;

      vector< pair<int,int>> v;

      for(i=0;i<n;i++)

      {

          cin>>a;

          v.push_back(make_pair(a,i+1));

      }

      sort(v.begin(),v.end()); //Sorting, but the vector of pairs is sorted according to first value of pair

      for(i=0;i<n/2;i++)

      {

          cout<<v[i].second<<" "<<v[n-1-i].second<<" "<<v[i].first<<endl;

      }

  }

Using Arrays

#include <bits/stdc++.h>

using namespace std;

int main() 

{

int n;    

cin>>n;

pair<int,int>a[100]  or a[n];  

for(int i=0;i<n;i++)

{

cin>>a[i].first;

a[i].second=i+1; // can also use another operation

}

sort(a,a+n);   

for(int i=0;i<n/2;i++)

cout<<a[i].second<<" "<<a[n-i-1].second<<endl;

}

pair of pair and pairs

#include<bits/stdc++.h>

using namespace std;

int main()

{

    pair<pair<int,int>,pair<int,int>>v[3];

    int i;

    for(i=0;i<3;i++)

    cin>>v[i].first.first>>v[i].first.second>>v[i].second.first>>v[i].second.second;

    sort(v,v+3);

    for(i=0;i<3;i++)

    {cout<<v[i].first.first<<" "<<v[i].first.second<<v[i].second.first<<" "<<v[i].second.second<<endl;}

}