Submission #425139

#	Time	Username	Problem	Language	Result	Execution time	Memory
425139		Mlxa	Carnival Tickets (IOI20_tickets)	C++14	39 / 100	1014 ms	88812 KiB

tickets

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) x.begin(), x.end()
#define mp make_pair
#define mt make_tuple
#define x first
#define y second
#include "tickets.h"
#include <vector>

const int N = 2000;
int cnt[N], lef[N], rig[N];

ll find_maximum(int k, vector<vector<int>> x) {
	int n = (int)x.size();
	int m = (int)x[0].size();
	vector<int> order;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			order.push_back(x[i][j]);
		}
	}
	sort(all(order));
	int bound = -1, best = n * m;
	for (int i = 1; i < (int)order.size(); ++i) {
		if (order[i] == order[i - 1]) {
			continue;
		}
		int val = abs(i - (n * m - i));
		if (best > val) {
			best = val;
			bound = order[i];
		}
	}
	vector<vector<int>> answer(n, vector<int>(m, -1));
	int ones = 0;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			cnt[i] += x[i][j] >= bound;
			ones += x[i][j] >= bound;
		}
	}
	fill_n(lef, n, 0);
	fill_n(rig, n, m - 1);

	vector<int> rows(n);
	iota(all(rows), 0);
	for (int i = 0; i < k; ++i) {
		sort(all(rows), [&](int ii, int jj) {
			return cnt[ii] < cnt[jj];
		});
		// cout << "--- " << i << endl;
		for (int j = 0; j < n / 2; ++j) {
			int sj = j;
			j = rows[j];
			// cout << "lef " << j << endl;
			cnt[j] -= x[j][lef[j]] >= bound;
			answer[j][lef[j]++] = i;
			j = sj;
		}
		for (int j = n / 2; j < n; ++j) {
			int sj = j;
			j = rows[j];
			// cout << "rig " << j << endl;
			cnt[j] -= x[j][rig[j]] >= bound;
			answer[j][rig[j]--] = i;
			j = sj;
		}
	}

	vector<vector<int>> res(k);
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			// cout << answer[i][j] << " ";
			if (answer[i][j] != -1) {
				res[answer[i][j]].push_back(x[i][j]);
			}
		}
		// cout << endl;
	}
	ll sum = 0;
	for (int i = 0; i < k; ++i) {
		sort(all(res[i]));
		assert((int)res[i].size() == n);
		for (int j = 0; j < n / 2; ++j) {
			sum += res[i][n - 1 - j] - res[i][j];
		}
	}
	allocate_tickets(answer);
	return sum;
}

#ifdef LC
#include "grader.cpp"
#endif

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