Submission #1091711

#	Time	Username	Problem	Language	Result	Execution time	Memory
1091711		KluydQ	Star triangles (IZhO11_triangle)	C++17	0 / 100	0 ms	348 KiB

triangle

#include <bits/stdc++.h>

#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )

using namespace std;
const int N = 1e6;

int a[N], b[N], x[N], y[N], a2[N], b2[N], tim;
long long ans = 0;

int main()
{
//	freopen("triangle.in", "r", stdin);
//	freopen("triangle.out", "w", stdout);
	
	int n; cin >> n;
	
	set <int> st;
	map <int, int> mp;
	
	FOR( i, 1, n, 1 ) cin >> x[i] >> y[i], st.insert( x[i] ), st.insert( y[i] );
	for( auto i : st ) mp[i] = ++ tim;
	
	FOR( i, 1, n, 1 )
	{
		x[i] = mp[x[i]], y[i] = mp[y[i]];
		b[y[i]] ++; 
		a2[x[i]] ++;
	}
	FOR( i, 1, n, 1 )
	{
		ans += a[x[i]] * 1ll * ( b[y[i]]  - 1 );
		a[x[i]] += ( b[y[i]] - 1 );
		ans += b2[y[i]] * 1ll * ( a2[x[i]] - 1 );
		b2[y[i]] += ( a2[x[i]] - 1 );
	}
	cout << ans;
}

• Subtask 1: 0 / 100