Submission #531525

#	Time	Username	Problem	Language	Result	Execution time	Memory
531525		christinelynn	Star triangles (IZhO11_triangle)	C++17	100 / 100	306 ms	13336 KiB

triangle

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll mod = 1e9 + 7;
#pragma GCC optimize("Ofast")
#define vi vector<int>
#define vll vector<ll>
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define sc second
#define endl '\n'
#define gl ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int main()
{
  gl
  int n;
  cin >> n;
  
  map<int, ll> x, y;
  vi a(n, 0), b(n, 0);
  
  for(int i = 0; i < n; i++){
    cin >> a[i] >> b[i];
    x[a[i]]++;
    y[b[i]]++;
  }
  
  ll ans = 0;
  
  for(int i = 0; i < n; i++){
    ans += (x[a[i]] - 1) * (y[b[i]] - 1);
  }
  
  cout << ans << endl;
}

• Subtask 1: 100 / 100