Submission #87938

#	Time	Username	Problem	Language	Result	Execution time	Memory
87938		turbat	Star triangles (IZhO11_triangle)	C++14	0 / 100	3 ms	376 KiB

triangle

#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
int n;
long long ans;
pair <int, int> p[300005];
map <int, int> my, mx;

int main (){
	freopen ("input.in", "r", stdin);
	freopen ("output.out", "w", stdout);	
	cin >> n;
	for (int i = 0;i < n;i++){
		cin >> p[i].F>> p[i].S;
		mx[p[i].F]++;
		my[p[i].S]++;
	}
	for (int i = 0;i < n;i++)
		ans += (mx[p[i].F] - 1) * (my[p[i].S] - 1);
	cout << ans<<endl;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:11:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen ("input.in", "r", stdin);
  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:12:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen ("output.out", "w", stdout); 
  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100