Submission #349636

#	Time	Username	Problem	Language	Result	Execution time	Memory
349636		my99n	Star triangles (IZhO11_triangle)	C++17	0 / 100	1 ms	364 KiB

triangle

#include<bits/stdc++.h>
using namespace std;

int x[300100], y[300100];
map<int,long long> mx, my;
int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n; cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> y[i];
    mx[x[i]]++; my[y[i]]++;
  }
  long long ans;
  for (int i = 0; i < n; i++) ans+=(mx[x[i]]-1)*(my[y[i]]-1);
  cout << ans;
  return 0;
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:15:34: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   15 |   for (int i = 0; i < n; i++) ans+=(mx[x[i]]-1)*(my[y[i]]-1);
      |                               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100