Submission #878475

#	Time	Username	Problem	Language	Result	Execution time	Memory
878475		Kak008723	Star triangles (IZhO11_triangle)	C++14	100 / 100	243 ms	12408 KiB

triangle

#include<bits/stdc++.h>
#define x first
#define y second
using namespace std;
const int N = 3e5+5;
pair<int,int> p[N];
map<int,int> mp,mp1;
int main(){
	ios::sync_with_stdio(0);cin.tie(0);
	cout.tie(0);
	int n,ans=0;
	cin>>n;
	for(int i=1;i<=n;i++) cin>>p[i].x>>p[i].y, mp[p[i].x]++,mp1[p[i].y]++;
	for(int i=1;i<=n;i++){
		ans += (long long )(mp[p[i].x]-1) * (long long )(mp1[p[i].y]-1);
	}
	cout<<ans;
}

• Subtask 1: 100 / 100