Submission #1268506

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268506		atillama	Star triangles (IZhO11_triangle)	C++20	100 / 100	384 ms	23332 KiB

triangle

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define int long long
#define double long double
#define pii pair<int, int>
#define pb push_back
#define F first
#define S second
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define debug(x) cout << #x << " = " << x << '\n';
#define vdebug(a) cout << #a << " = "; for(auto x : a) cout << x << " "; cout << '\n';

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> indexed_pair_set;

const double eps = 1e-9;
const int mod = 1e9 + 7;
const int N = 2e5 + 5;
const int INF = 1e18;

void solve(){
    int n; cin >> n;
    map<int, int> mp1, mp2;
    set<pii> cords;
    for(int i = 0; i < n; i++){
        int x, y; cin >> x >> y;
        mp1[x]++; mp2[y]++;
        cords.insert({x, y});
    }
    int ans = 0;
    for(auto [x, y] : cords){
        ans += (mp1[x] - 1) * (mp2[y] - 1);
    }
    cout << ans << '\n';
}

signed main(){
    fastio;
    solve();
}

/*
    freopen("x.in", "r", stdin);
    freopen("x.out", "w", stdout);
*/

//atilla

• Subtask 1: 100 / 100