Submission #671593

#	Time	Username	Problem	Language	Result	Execution time	Memory
671593		Baytoro	Star triangles (IZhO11_triangle)	C++17	100 / 100	300 ms	12600 KiB

triangle

#include <bits/stdc++.h>
using namespace std;
#define ios ios::sync_with_stdio(false); cin.tie(NULL);
#define pb push_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fr first
#define sc second
#define int long long
#define endl '\n'
void fopn(string name){
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
}
const int INF=1e9+9,mod=1e9+7;
int n,m;
void solve(){
	cin>>n;
	map<int,int> x,y;
	vector<pair<int,int>> vec;
	for(int i=0;i<n;i++){
		int a,b;cin>>a>>b;
		vec.pb({a,b});
		x[a]++,y[b]++;
	}
	int res=0;
	for(int i=0;i<n;i++){
		res+=(x[vec[i].fr]-1)*(y[vec[i].sc]-1);
	}
	cout<<res;
}
main(){
	ios;
	int T=1;
	//cin>>T;
	while(T--){
		solve();
	}
}

Compilation message (stderr)

triangle.cpp:32:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   32 | main(){
      | ^~~~
triangle.cpp: In function 'void fopn(std::string)':
triangle.cpp:12:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |  freopen((name+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
triangle.cpp:13:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   13 |  freopen((name+".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100