Submission #1307073

#	Time	Username	Problem	Language	Result	Execution time	Memory
1307073		dang_hai_long	Star triangles (IZhO11_triangle)	C++20	0 / 100	1 ms	572 KiB

triangle

#include <bits/stdc++.h>

using namespace std;

int main() {
	int n;
	cin >> n;
	map<int, int> row, col;
	vector <pair<int, int>> a(n);
	for (auto &x:a) {
		cin >> x.first >> x.second;
		row[x.first]++;
		col[x.second]++;
	}
	int res = 0;
	for (auto &x:a) {
		res += (row[x.first] - 1) * (row[x.second] - 1);
	}
	cout << res << "\n";
	
	return 0;
}

• Subtask 1: 0 / 100