Submission #333818

#	Time	Username	Problem	Language	Result	Execution time	Memory
333818		limabeans	Star triangles (IZhO11_triangle)	C++17	100 / 100	1014 ms	20560 KiB

triangle

#include <bits/stdc++.h>
using namespace std;

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl





using ll = long long;




int n;
vector<pair<int,int>> a;
map<int,vector<int>> byX, byY;


int getLess(int x, const vector<int>& w) {
    auto iter = lower_bound(w.begin(),w.end(),x);
    if (iter==w.begin()) return 0;
    --iter;
    return iter - w.begin() + 1;
}

int getGreater(int x, const vector<int>& w) {
    auto iter = upper_bound(w.begin(),w.end(),x);
    return w.end() - iter;
}


int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);

    cin>>n;
    a.resize(n);
    for (int i=0; i<n; i++) {
	cin>>a[i].first>>a[i].second;
	byX[a[i].first].push_back(a[i].second);
	byY[a[i].second].push_back(a[i].first);
    }

    for (auto &p: byX) {
	sort(p.second.begin(), p.second.end());
    }
    for (auto &p: byY) {
	sort(p.second.begin(), p.second.end());
    }


    ll res = 0;

    for (auto p: a) {
	int x = p.first;
	int y = p.second;
	res += 1ll*getLess(y,byX[x])*getLess(x,byY[y]);
	res += 1ll*getLess(y,byX[x])*getGreater(x,byY[y]);
	res += 1ll*getGreater(y,byX[x])*getLess(x,byY[y]);
	res += 1ll*getGreater(y,byX[x])*getGreater(x,byY[y]);
    }


    cout<<res<<endl;    
    return 0;
}

• Subtask 1: 100 / 100