Submission #379588

#	Time	Username	Problem	Language	Result	Execution time	Memory
379588		penguinhacker	Star triangles (IZhO11_triangle)	C++14	100 / 100	208 ms	10712 KiB

triangle

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

#define ll long long
#define ar array

int n, x[300000], y[300000], cx[300000], cy[300000];
void compress(int a[]) {
	vector<int> d(a, a + n);
	sort(d.begin(), d.end());
	d.resize(unique(d.begin(), d.end()) - d.begin());
	for (int i = 0; i < n; ++i)
		a[i] = lower_bound(d.begin(), d.end(), a[i]) - d.begin();
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	for (int i = 0; i < n; ++i)
		cin >> x[i] >> y[i];
	compress(x);
	compress(y);
	for (int i = 0; i < n; ++i)
		++cx[x[i]], ++cy[y[i]];
	ll ans = 0;
	for (int i = 0; i < n; ++i)
		ans += (ll)(cx[x[i]] - 1) * (cy[y[i]] - 1);
	cout << ans;
	return 0;
}

• Subtask 1: 100 / 100