Submission #839213

#	Time	Username	Problem	Language	Result	Execution time	Memory
839213		Alfraganus	Star triangles (IZhO11_triangle)	C++17	0 / 100	1 ms	212 KiB

triangle

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

#define fs first
#define ss second
#define ll long long

int main(){
    int n;
    cin >> n;
    map<int, int> X, Y;
    vector<pair<int, int>> a(n);
    for(int i = 0; i < n; i ++){
        cin >> a[i].fs >> a[i].ss;
        X[a[i].fs] ++;
        Y[a[i].ss] ++;
    }
    ll ans = 0;
    for(int i = 0; i < n; i ++)
        ans += 1ll * X[a[i].fs] * Y[a[i].ss];
    cout << ans;
}

• Subtask 1: 0 / 100