Submission #680208

#	Time	Username	Problem	Language	Result	Execution time	Memory
680208		Angus_Yeung	Star triangles (IZhO11_triangle)	C++17	100 / 100	330 ms	15552 KiB

triangle

#include <bits/stdc++.h>
#define x first
#define y second
#define pii pair<ll, ll>
typedef long long ll;
const ll MOD = 1000000007LL;
const ll INF = 1e18;
using namespace std;

ll n, x[300010], y[300010], ans;
map<ll, ll> mx, my;

int main() {
	cin.tie(0); cout.tie(0);
	ios::sync_with_stdio(0);

	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> x[i] >> y[i];
		mx[x[i]]++;
		my[y[i]]++;
	}
	
	ans = 0;
	for (int i = 1; i <= n; i++) {
		ans += (mx[x[i]]-1)*(my[y[i]]-1);
	}
	cout << ans << "\n";

	return 0;
}

• Subtask 1: 100 / 100