Submission #1057125

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057125		aufan	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	401 ms	63260 KiB

tickets

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

using namespace std;

long long find_maximum(int k, vector<vector<int>> a) {
	int n = (int)a.size(), m = (int)a[0].size();
	long long res = 0;
	vector<vector<int>> bad(n, vector<int>(m));
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < k; j++) {
			res -= a[i][j];
		}
	}

	priority_queue<array<int, 3>> pq;
	for (int i = 0; i < n; i++) {
		pq.push({a[i][m - 1] + a[i][k - 1], i, 0});
	}

	vector<int> cnt(n, k);
	for (int i = 0; i < n * k / 2; i++) {
		auto [x, j, d] = pq.top();
		pq.pop();

		res += x;
		cnt[j] -= 1;
		if (d + 1 <= k - 1) pq.push({a[j][m - 1 - (d + 1)] + a[j][k - 1 - (d + 1)], j, d + 1});
	}

	vector<int> pl(n, 0), pr(n, m - 1);
	vector<vector<int>> ans(n, vector<int>(m, -1));
	for (int i = 0; i < k; i++) {
		vector<int> ord(n);
		iota(ord.begin(), ord.end(), 0);
		sort(ord.begin(), ord.end(), [&](int x, int y) {
			return cnt[x] > cnt[y];
		});
		
		for (int j = 0; j < n / 2; j++) {
			ans[ord[j]][pl[ord[j]]++] = i;
			cnt[ord[j]] -= 1;
		}

		for (int j = n / 2; j < n; j++) {
			ans[ord[j]][pr[ord[j]]--] = i;
		}
	}

	allocate_tickets(ans);

	return res;
}

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