제출 #87931

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
87931		turbat	별들과 삼각형 (IZhO11_triangle)	C++14	0 / 100	2 ms	252 KiB

triangle

/* 
ID: turbat_1
TASK: sort3
LANG: C++
*/
#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("triangles.in.in", "r",  stdin);
	freopen("triangles.in.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;
}

컴파일 시 표준 에러 (stderr) 메시지

triangle.cpp: In function 'int main()':
triangle.cpp:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("triangles.in.in", "r",  stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:17:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("triangles.in.out", "w", stdout);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100