Submission #1308534

#	Time	Username	Problem	Language	Result	Execution time	Memory
1308534		buinamkhanh	Star triangles (IZhO11_triangle)	C++20	0 / 100	1 ms	332 KiB

triangle

#include <iostream>
#define int long long
using namespace std;
int n,x[300005],y[300005],a1,a2,ans=0;
signed main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	freopen("triangles.in","r",stdin);
	freopen("triangles.out","w",stdout);
	cin>>n;
	for (int i=1; i<=n; i++)
		cin>>x[i]>>y[i];
	for (int i=1; i<=n; i++) {
		a1=-1;a2=-1;
		for (int j=1; j<=n; j++) {
			if (x[j]==x[i]) a1++;
			if (y[j]==y[i]) a2++;
		}
		ans+=a1*a2;
	}
	cout<<ans;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:8:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |         freopen("triangles.in","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:9:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |         freopen("triangles.out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100