Submission #499692

#	Time	Username	Problem	Language	Result	Execution time	Memory
499692		PoPularPlusPlus	Star triangles (IZhO11_triangle)	C++17	100 / 100	182 ms	11244 KiB

triangle

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long 
#define pb(e) push_back(e)
#define sv(a) sort(a.begin(),a.end())
#define sa(a,n) sort(a,a+n)
#define mp(a,b) make_pair(a,b)
#define vf first
#define vs second
#define ar array
#define all(x) x.begin(),x.end()
const int inf = 0x3f3f3f3f;
const ll mod = 998244353 ; 
const double PI=3.14159265358979323846264338327950288419716939937510582097494459230;
bool remender(ll a , ll b){return a%b;}

bool cmp(pair<int,int> a  ,pair<int,int> b){
	return a.vs < b.vs;
}

void solve(){
	int n;
	cin >> n;
	vector<pair<int,int>> v;
	for(int i = 0; i < n; i++){
		int x , y;
		 cin >> x >> y;
		 v.pb(mp(x,y));
	}
	sort(all(v) , cmp);
	ll ans = 0;
	map<int,ll> m;
	for(int i = 0; i < n; i++){
		ll cnt = 1;
		int j = i + 1;
		while(j < n && v[j].vs == v[i].vs){
			j++;
			cnt++;
		}
		i = j - 1;
		m[v[i].vs] = cnt;
	}
	sv(v);
	
	for(int i = 0; i < n; i++){
		ll cnt = 1;
		int j = i + 1; 
		while(j < n && v[j].vf == v[i].vf){
			j++;
			cnt++;
		}
		for(int k = i; k < j; k++){
			ans += (cnt - 1LL) * (m[v[k].vs]-1LL);
		}
		i = j - 1;
	}
	cout << ans << '\n';
}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//freopen("rblock.in", "r", stdin);
//freopen("rblock.out", "w", stdout);
	//int t;cin >> t;while(t--)
	solve();
	return 0;
}

• Subtask 1: 100 / 100