Submission #20815

#	Time	Username	Problem	Language	Result	Execution time	Memory
20815		jjwdi0	Star triangles (IZhO11_triangle)	C++11	100 / 100	1293 ms	36344 KiB

triangle

#include <bits/stdc++.h>
#define sz(x) ((int)(x).size())
using namespace std;

map<int, set<int>> s1, s2;
int N;
long long ans;

int main() {
	scanf("%d", &N);
	for(int i=0, x, y; i<N; i++) {
		scanf("%d %d", &x, &y);
		s1[x].insert(y);
		s2[y].insert(x);
	}
	for(auto itr : s1) {
        int i = itr.first;
		if(sz(s1[i]) >= 2) {
			for(auto it : s1[i]) {
				ans += (long long)(sz(s1[i]) - 1) * (sz(s2[it]) - 1);
			}
		}
	}
	printf("%lld", ans);
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:10:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
                 ^
triangle.cpp:12:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &x, &y);
                         ^

• Subtask 1: 100 / 100