Submission #1204935

#	Time	Username	Problem	Language	Result	Execution time	Memory
1204935		bangan	Carnival Tickets (IOI20_tickets)	C++20	11 / 100	1 ms	836 KiB

tickets

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

using i64 = long long;

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

	std::vector<std::pair<int, int>> all;
	std::vector tag(n, std::vector<int>(m));
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			all.emplace_back(i, j);
		}
	}
	std::sort(all.begin(), all.end(), [&](auto a, auto b) {
		auto [i0, j0] = a;
		auto [i1, j1] = b;
		return x[i0][j0] > x[i1][j1];
	});
	all.resize(k * n / 2);

	for (auto pair : all) {
		auto [i, j] = pair;
		tag[i][j] = 1;
	}

	std::vector pre(n, std::vector<i64>(m + 1));
	for (int i = 0; i < n; i++) {
		for (int j = 1; j <= m; j++) {
			pre[i][j] = pre[i][j - 1] + tag[i][j - 1];
		}
	}

	i64 S = 0;
	std::vector<int> l(n, 0), r(n, m - 1);
	std::vector ans(n, std::vector<int>(m, -1));

	for (int round = 0; round < k; round++) {
		for (int i = 0; i < n; i++) {
			ans[i][l[i]] = round;
			S -= x[i][l[i]++];
		}
		
		std::vector<int> ord(n);
		iota(ord.begin(), ord.end(), 0);
		std::sort(ord.begin(), ord.end(), [&](int i, int j) {
			return pre[i][r[i] + 1] - pre[i][l[i] - 1] > pre[j][r[j] + 1] - pre[j][l[j] - 1];
		});
		ord.resize(n / 2);
	
		for (int i : ord) {
			S += x[i][--l[i]] + x[i][r[i]];
			ans[i][l[i]] = -1;
			ans[i][r[i]--] = round;
		}
	}

	allocate_tickets(ans);
	return S;
}

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