Submission #920312

#	Time	Username	Problem	Language	Result	Execution time	Memory
920312		zeta7532	Star triangles (IZhO11_triangle)	C++17	100 / 100	279 ms	18008 KiB

triangle

#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
const ll mod = 998244353;
#define fi first
#define se second
#define rep(i,n) for(ll i=0;i<n;i++)
#define all(x) x.begin(),x.end()
#define faster ios::sync_with_stdio(false);cin.tie(nullptr)

int main() {
    ll N;
    cin >> N;
    vector<ll> X(N),Y(N);
    rep(i,N) cin >> X[i] >> Y[i];
    vector<ll> x=X,y=Y;
    sort(all(x));
    x.erase(unique(all(x)),x.end());
    sort(all(y));
    y.erase(unique(all(y)),y.end());
    rep(i,N) X[i]=lower_bound(all(x),X[i])-x.begin();
    rep(i,N) Y[i]=lower_bound(all(y),Y[i])-y.begin();
    vector<ll> cntX(300500,0),cntY(300500,0);
    rep(i,N) cntX[X[i]]++;
    rep(i,N) cntY[Y[i]]++;
    ll ans=0;
    rep(i,N){
        ans+=(cntX[X[i]]-1)*(cntY[Y[i]]-1);
    }
    cout << ans << endl;
    return 0;
}

• Subtask 1: 100 / 100