Submission #1197962

#	Time	Username	Problem	Language	Result	Execution time	Memory
1197962		countless	Carnival Tickets (IOI20_tickets)	C++20	27 / 100	306 ms	60268 KiB

tickets

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

typedef long long ll;
typedef long double ld;

const ll MOD = 998244353;
const ll INF = 1e18;
const ld EPS = 1e-12;

#define endl "\n"
#define sp <<" "<<
#define REP(i, a, b) for(ll i = a; i < b; i++)
#define dbg(x) cout << #x << " = " << x << endl
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fast_io() ios_base::sync_with_stdio(false); cin.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())

struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		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);
	}
};

template <typename Key, typename Value>
using hash_map = unordered_map<Key, Value, custom_hash>;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// uniform_int_distribution<int>(a, b)(rng);
// shuffle(all(a), rng);

ll find_maximum(int k, vector<vector<int>> x) {
	ll n = x.size();
	ll m = x[0].size();

	assert(k == 1);

	ll ans = 0;

	// sort by val, keep track of pos
	vector<vector<int>> pos(n, vector<int>(m));
	REP(i, 0, n) {
		REP(j, 0, m) {
			pos[i][j] = j;
		}

		sort(all(pos[i]), [&](const int &a, const int &b) -> bool {
			return x[i][a] < x[i][b];
		});
	}

	auto find = [&](const int &i, const int &j) {
		return x[i][pos[i][j]];
	};

	priority_queue<pair<int, int>> pq;

	// b will always be median
	// ans will always be greatest n/2 minus smallest n/2
	REP(i, 0, n) {
		// take smallest k
		ans -= find(i, 0);

		pq.push({find(i, m-1) + find(i, 0), i});
	}

	// take greatest n/2 paired with its smallest to balance sum properly
	vector<bool> use(n, false);
	REP(i, 0, n / 2) {
		pair<int, int> cand = pq.top(); pq.pop();
		ans += cand.first;

		use[cand.second] = true;
	}

	vector<vector<int>> g(n, vector<int>(m, -1));

	// apply
	REP(j, 0, n) {
		if (use[j]) {
			g[j][pos[j][m-1]] = 0;
		} else {
			g[j][pos[j][0]] = 0;
		}
	}

	allocate_tickets(g);

	return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10