Submission #301276

#	Time	Username	Problem	Language	Result	Execution time	Memory
301276		Khongor	Carnival Tickets (IOI20_tickets)	C++14	41 / 100	1388 ms	108776 KiB

tickets

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

vector<vector<int>> ans;

// 1 5
// 10 10
// 8 12
// 12 20

const int MAX = 1555;
long long dp[MAX][MAX];

long long find_maximum(int k, std::vector<std::vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	ans = vector<vector<int>>(n, vector<int>(m, -1));

	long long res = 0;
	vector<pair<int, pair<int, int>>> all;
	for (int i = 0; i < n; i++)
		for (int j = 0; j < m; j++)
			all.push_back({x[i][j], {i, j}});
	sort(all.begin(), all.end());
	vector<vector<pair<int, int>>> high(n), pickedLow(n), pickedHigh(n);
	int median = (all[n * m / 2].first + all[n * m / 2 - 1].first) / 2;

	int cnt = 0;
	for (int i = 0; i < all.size(); i++) {
		int color = all[i].second.first;
		int ticket = all[i].second.second;
		if (i < all.size() / 2) {
			if (pickedLow[color].size() < k)  {
				pickedLow[color].push_back({median - all[i].first, ticket});
				cnt++;
				res += median - all[i].first;
			}
		} else {
			high[color].push_back({all[i].first - median, ticket});
		}
	}
	for (int i = 0; i < n; i++) {
		while (pickedLow[i].size() + pickedHigh[i].size() < k) {
			res += high[i].back().first;
			pickedHigh[i].push_back(high[i].back());
			high[i].pop_back();
		}
	}

	int need = cnt - n * k / 2;
	while (need--) {
		int idx = -1, best = 0;
		for (int i = 0; i < n; i++) {
			int cur;
			// assert(pickedLow[i].size() > 0 || high[i].size() > 0);

			if (high[i].empty() || pickedLow[i].empty()) continue;
			cur = high[i].back().first - pickedLow[i].back().first;

			if (idx == -1 || cur > best) {
				best = cur;
				idx = i;
			}
		}

		assert(idx != -1);

		// switch
		res += best;
		if (pickedLow[idx].size() > 0) pickedLow[idx].pop_back();
		pickedHigh[idx].push_back(high[idx].back());
		high[idx].pop_back();
	}

	int cntNeg = 0, cntPos = 0;
	for (int i = 0; i < n; i++) {
		cntNeg += pickedLow[i].size();
		cntPos += pickedHigh[i].size();
		assert(pickedLow[i].size() + pickedHigh[i].size() == k);
	}
	assert(cntNeg + cntPos == n * k);
	assert(cntNeg == n * k / 2);

	for (int r = 0; r < k; r++) {
		vector<bool> used(n);
		vector<pair<int, int>> counts;
		for (int i = 0; i < n; i++) counts.push_back({pickedLow[i].size(), i});
		sort(counts.rbegin(), counts.rend());

		int taken = 0;
		for (int ii = 0; ii < n; ii++) {
			int i = counts[ii].second;
			if (pickedLow[i].size() > 0) {
				used[i] = true;
				taken++;
				ans[i][pickedLow[i].back().second] = r;
				pickedLow[i].pop_back();
			}
			if (taken == n / 2) break;
		}
		taken = 0;
		for (int i = 0; i < n; i++) {
			if (pickedHigh[i].size() > 0 && !used[i]) {
				taken++;
				ans[i][pickedHigh[i].back().second] = r;
				pickedHigh[i].pop_back();
			}
			if (taken == n / 2) break;
		}
	}

	allocate_tickets(ans);
	return res;
}

// a b a c
// c b d d

Compilation message (stderr)

tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:30:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |  for (int i = 0; i < all.size(); i++) {
      |                  ~~^~~~~~~~~~~~
tickets.cpp:33:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |   if (i < all.size() / 2) {
      |       ~~^~~~~~~~~~~~~~~~
tickets.cpp:34:32: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   34 |    if (pickedLow[color].size() < k)  {
      |        ~~~~~~~~~~~~~~~~~~~~~~~~^~~
tickets.cpp:44:53: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   44 |   while (pickedLow[i].size() + pickedHigh[i].size() < k) {
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from /usr/include/c++/9/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:33,
                 from tickets.cpp:2:
tickets.cpp:80:53: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   80 |   assert(pickedLow[i].size() + pickedHigh[i].size() == k);
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~

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