Submission #1100628

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100628		vjudge1	Star triangles (IZhO11_triangle)	C++17	100 / 100	236 ms	22412 KiB

triangle

//#include <bits/stdc++.h>

#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <random>


using namespace std;
using ll = long long;

#define int long long

const int N = 6e5 + 7;
const int M = 1e9 + 7;

struct custom_hash { //unordered_map<long long, int, custom_hash> safe_map; gp_hash_table<long long, int, custom_hash> safe_hash_table;

    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

int binpow(int a, int n, int m) {
    int res = 1;
    while (n) {
        if (n & 1) res = res * a % m;
        a = a * a % m;
        n >>= 1;
    }
    return res;
}

/*inline void factorials(int n) {
    f[0] = 1;
    for(int i = 1; i <= n; i++) {
        f[i] = (f[i - 1] * i) % M;
    }
    invf[n] = binpow(f[n], M - 2, M);
    for(int i = n - 1; i >= 0; i--) {
        invf[i] = (invf[i + 1] * (i + 1)) % M;
    }
}

inline int cnk(int n, int k) {
    if(k > n) {
        return 0;
    }
    return (((f[n] * invf[n - k]) % M) * invf[k]) % M;
} */

int a[N], b[N], c[N];
set<int> ms;
int xx[N], yy[N];
vector<pair<int, int>> vv, uu;
unordered_map<int, int, custom_hash> mp, mp2, val;

inline void Solve() {
    int n;
    cin >> n;
    for(int i = 1; i <= n; i++) {
        int x, y;
        cin >> x >> y;
        vv.push_back({x, y});
        uu.push_back({y, x});
        ms.insert(x);
        ms.insert(y);
    }
    
    sort(vv.begin(), vv.end());
    sort(uu.begin(), uu.end());
    
    int nw = 1;
    for(auto to : ms) {
        val[to] = nw;
        nw++;
    }
    for(int i = 1; i <= n; i++) {
        xx[val[vv[i - 1].first]]++;
        yy[val[vv[i - 1].second]]++;
    }
    
    int ans = 0;
    
    for(int i = 0; i < n; i++) {
        ans += (yy[val[vv[i].second]] - 1) * (xx[val[vv[i].first]] - 1);
    }
    //cout << val[vv[1ll].first] << ' ';
    //cout << ans << ' ';
    for(int i = 0; i < n; i++) {
        ans += (xx[val[uu[i].second]] - 1) * (yy[val[uu[i].first]] - 1);
    }
    cout << ans / 2;
}

signed main() {
    //freopen("brackets.in", "r", stdin);
    //freopen("brackets.out", "w", stdout);
    
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    
    int t = 1;
    //cin >> t;
    //cout << '\n' << '\n';
    
    while(t--) {
        Solve();
    }
    
    return 0;
}

/*
 Special cases n = 1 or just 1?
 u r using unsigned long long which can't carry negative values?
 what if u r doing the same thing n times, it may cause the TL
 make sure that the size of your massives, vectors are enough
*/

• Subtask 1: 100 / 100