Submission #1243502

#	Time	Username	Problem	Language	Result	Execution time	Memory
1243502		snowysmo	Star triangles (IZhO11_triangle)	C++20	100 / 100	363 ms	7160 KiB

triangle

#include<bits/stdc++.h>
#define ll long long
#define endl '\n'

using namespace std;

int main(){
    int n; cin>>n;
    map<ll, pair<ll, ll>> mp;
    ll a[n+1], b[n+1];
    for(int i=1;i<=n;i++){
        cin>>a[i]>>b[i];
        ll x=a[i], y=b[i];
        if(!mp.count(x)) mp[x].first=1, mp[x].second=0;
        else mp[x].first++;
        if(!mp.count(y)) mp[y].first=0, mp[y].second=1;
        else mp[y].second++;
    }
    ll ans=0;
    for(int i=1;i<=n;i++){
        ll x=a[i], y=b[i];
        ll xx=mp[y].second-1, yy=mp[x].first-1;
        ans+=xx*yy;
    }
    cout<<ans<<endl;



    return 0;
}

• Subtask 1: 100 / 100