Submission #1108150

#	Time	Username	Problem	Language	Result	Execution time	Memory
1108150		Tsagana	Star triangles (IZhO11_triangle)	C++17	0 / 100	4 ms	592 KiB

triangle

#include<bits/stdc++.h>

#define IOS ios_base::sync_with_stdio(false);cin.tie();cout.tie();
#define all(x) x.begin(), x.end()
#define lnl long long
#define pq priority_queue
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define pp pop_back
#define F first
#define S second

using namespace std;

vector<pair<int, int>> vx;
vector<pair<int, int>> vy;
vector<pair<int, int>> p;
int X[300001];
int Y[300001];

void solve () {
	int n; cin >> n;
	for (int i = 0; i < n; i++) {
		int x, y; cin >> x >> y;
		vx.pb({x, i});
		vy.pb({y, i});
		p.pb({x, y});
	}
	sort(all(vx));
	sort(all(vy));

	int l = 0; p[vx[0].S].F = 0;
	for (int i = 1; i < n; i++) {
		if (vx[i].F != vx[i-1].F) l++;
		p[vx[i].S].F = l;
	}
	int r = 0; p[vy[0].S].S = 0;
	for (int i = 1; i < n; i++) {
		if (vy[i].F != vy[i-1].F) r++;
		p[vy[i].S].S = r;
	}

	for (auto i: p) {
		X[i.F]++; Y[i.S]++;
	}
	int ans = 0;
	for (auto i: p) {
		ans += (X[i.F]-1)*(Y[i.S]-1);
	}
	cout << ans;
}
signed main() {
	IOS 
	#ifndef LOCAL
		freopen("triangles.in", "r", stdin);
		freopen("triangles.out", "w", stdout);
	#endif

	solve();
	return 0;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:57:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |   freopen("triangles.in", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:58:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |   freopen("triangles.out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100