Submission #1204959

#	Time	Username	Problem	Language	Result	Execution time	Memory
1204959		bangan	Carnival Tickets (IOI20_tickets)	C++20	11 / 100	300 ms	51580 KiB

tickets

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

using i64 = long long;

std::pair<i64, std::vector<std::vector<int>>> solve_simple(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;
		if (x[i0][j0] == x[i1][j1]) {
			return j0 > j1;
		} else {
			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;
		}
	}

	return {S, ans};
}

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

	std::vector<int> l(n, k - 1), r(n, m - 1);
	auto cmp = [&](int i, int j) {
		return x[i][l[i]] + x[i][r[i]] < x[j][l[j]] + x[j][r[j]];
	};

	std::priority_queue<int, std::vector<int>, decltype(cmp)> pq(cmp);
	for (int i = 0; i < n; i++) {
		pq.push(i);
	}

	i64 rep = k * n / 2;
	while (rep--) {
		int i = pq.top();
		pq.pop();

		l[i]--;
		r[i]--;
		if (l[i] < r[i]) {
			pq.push(i);
		}
	}

	std::vector<std::vector<int>> opt_x;
	for (int i = 0; i < n; i++) {
		std::vector<int> row;
		for (int j = 0; j <= l[i]; j++) {
			row.push_back(x[i][j]);
		}
		for (int j = r[i] + 1; j < m; j++) {
			row.push_back(x[i][j]);
		}
		opt_x.push_back(row);
	}
	auto [S, par_ans] = solve_simple(k, opt_x);

	std::vector ans(n, std::vector<int>(m, -1));
	for (int i = 0; i < n; i++) {
		int j = 0;
		for (int jj = 0; jj <= l[i]; jj++) {
			ans[i][jj] = par_ans[i][j++];
		}
		for (int jj = r[i] + 1; jj < m; jj++) {
			ans[i][jj] = par_ans[i][j++];
		}
	}

	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