Submission #170973

#	Time	Username	Problem	Language	Result	Execution time	Memory
170973		achibasadzishvili	Star triangles (IZhO11_triangle)	C++14	100 / 100	549 ms	15708 KiB

triangle

#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
using namespace std;
ll n,x[300005],ans,y[300005];
map<ll,ll>a,b;
int main(){
    ios::sync_with_stdio(false);
    cin >> n;
    for(int i=1; i<=n; i++){
        cin >> x[i] >> y[i];
        a[x[i]]++;
        b[y[i]]++;
    }
    for(int i=1; i<=n; i++)
        ans += (a[x[i]] - 1) * (b[y[i]] - 1);
    cout << ans << endl;
    
    
    
    
    return 0;
}

• Subtask 1: 100 / 100