650A. Watchmen - Codeforces Solution C++ ~ CodingWithArt

➤ Problem Link : 650A. Watchmen

✅ C++ Solution :

 
#include<bits/stdc++.h>
using namespace std;
 
#define ll long long int
 
int main()
{
  ll n,x,y;
  cin>>n;
  unordered_map<ll,ll> xmp,ymp;
  map<pair<ll,ll>, ll  > st;
  for(int i=0;i<n;i++)
  {
 
    cin>>x>>y;
    xmp[x]++;
    ymp[y]++;
    st[make_pair(x,y)]++;
  }
 
  long double cnt=0;
 
  for(auto it=xmp.begin();it!=xmp.end();it++)
    cnt+=((it->second)*(it->second-1))/2;
 
  for(auto it=ymp.begin();it!=ymp.end();it++)
    cnt+=((it->second)*(it->second-1))/2;
    
    for(auto it=st.begin();it!=st.end();it++)
        cnt-=((it->second)*(it->second-1))/2;
    
  cout<<(ll)cnt;
 
}

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About Utkarsh Gupta

I am a Member Technical at D.E. Shaw India Pvt. Ltd. CodingWithArt is a blog where you find tricks and solutions to challenging coding and development problems. I aim to build a universal tech platform for every enthusiast out there.