Submission #671482

#	Time	Username	Problem	Language	Result	Execution time	Memory
671482		Alihan_8	Star triangles (IZhO11_triangle)	C++17	100 / 100	436 ms	26440 KiB

triangle

#include <bits/stdc++.h>
// include <ext/pb_ds/assoc_container.hpp>
// include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
using namespace std;
#define all(x) x.begin(), x.end()
#define pb push_back
// define ordered_set tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>
#define mpr make_pair
#define ln '\n'
void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
#define int long long
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n; cin >> n;
    vector <int> x(n), y(n);
    map <int,vector<int>> mpx, mpy;
    for ( int i = 0; i < n; i++ ){
        cin >> x[i] >> y[i];
        mpx[y[i]].pb(x[i]);
        mpy[x[i]].pb(y[i]);
    }
    int cnt = 0;
    for ( int i = 0; i < n; i++ ){
        int l = x[i], r = y[i];
        cnt += ((int)mpx[r].size()-1)*((int)mpy[l].size()-1);
    }
    cout << cnt;

    cout << '\n';
}

Compilation message (stderr)

triangle.cpp: In function 'void IO(std::string)':
triangle.cpp:11:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:11:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100