Submission #293861

#	Time	Username	Problem	Language	Result	Execution time	Memory
293861		7_7_7	Star triangles (IZhO11_triangle)	C++17	0 / 100	2 ms	384 KiB

triangle

#include <bits/stdc++.h>

using namespace std;

int n;
map<int, int> x;
map<int, int> y;
int main()
{
    ios_base::sync_with_stdio(false);

    freopen("triangles.in", "r", stdin);
    freopen("triangles.out", "w", stdout);

    cin >> n;
    vector<int> a(n + 1), b(n + 1);
    for(int i = 1; i <= n; i ++){
        cin >> a[i] >> b[i];
        x[a[i]] ++; y[b[i]] ++;
    }
    long long res = 0;
    for(int i = 1; i <= n; i ++){
        x[a[i]] --; y[b[i]] --;
        res += (x[a[i]] * 1ll * y[b[i]]);
        x[a[i]] ++; y[b[i]] ++;
    }
    cout << res << "\n";
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:12:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   12 |     freopen("triangles.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:13:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   13 |     freopen("triangles.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100