Submission #1109686

#	Time	Username	Problem	Language	Result	Execution time	Memory
1109686		Anar	Star triangles (IZhO11_triangle)	C++14	100 / 100	231 ms	22156 KiB

triangle

#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <array>
#include <map>
#include <iterator>

using namespace std;

#define pb push_back
#define ll long long
#define ff first
#define ss second
#define fastio ios_base::sync_with_stdio(false); cin.tie(nullptr);

typedef pair<int,int> pii;
typedef vector<ll> vi;
typedef vector<pii> vii;
typedef vector<vi> vvi;
typedef vector<bool> vb;
typedef vector<vb> vvb;

int n, ans;
vi starx, stary;
vii star;

map <int, int> mpx;
map <int, int> mpy;

void preprocess() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int x, y;
        cin >> x >> y;
        starx.pb(x);
        stary.pb(y);
        star.pb({x, y});
    }
    sort(starx.begin(), starx.end());
    sort(stary.begin(), stary.end());
}

void mainprocess() {
    for (int i = 0; i < n; i++) {
        mpx[starx[i]] ++;
        mpy[stary[i]] ++;
    }
    for (int i = 0; i < n; i++) {
        ans += (mpx[star[i].ff] - 1) *  (mpy[star[i].ss] - 1);
    }
}

signed main() {
    fastio;
    preprocess();
    mainprocess();
    cout << ans;
}

• Subtask 1: 100 / 100