Submission #1016737

#	Time	Username	Problem	Language	Result	Execution time	Memory
1016737		aykhn	Carnival Tickets (IOI20_tickets)	C++17	100 / 100	478 ms	76120 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
 
using namespace std;
 
#define inf 0x3F3F3F3F3F3F3F3F
 
long long find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> answer(n, vector<int> (m, -1));
	vector<long long> taken(n, 0);
	long long s = n * k / 2;
	priority_queue<array<int, 3>> pq;
	for (int i = 0; i < n; i++)
	{
		pq.push({x[i][m - 1] + x[i][k - 1], i, 0});
	}
	while (s)
	{
		array<int, 3> y = pq.top();
		pq.pop();
		taken[y[1]]++;
		s--;
		if (m - y[2] - 2 >= m - k) pq.push({x[y[1]][m - y[2] - 2] + x[y[1]][k - y[2] - 2], y[1], y[2] + 1});
	}
	vector<long long> l(n, 0), r(n, 0);
	for (int i = 0; i < n; i++)
	{
		r[i] = m - taken[i];
	}
	assert(!s);
	vector<int> o(n);
	iota(o.begin(), o.end(), 0);
	long long res = 0;
	for (int t = 0; t < k; t++)
	{
		sort(o.begin(), o.end(), [&](const int &a, const int &b)
		{
			return r[a] < r[b];
		});
		for (int i = 0; i < o.size() / 2; i++)
		{
			res += x[o[i]][r[o[i]]];
			answer[o[i]][r[o[i]]] = t;
			r[o[i]]++;
		}
		for (int i = o.size() / 2; i < o.size(); i++)
		{
			res -= x[o[i]][l[o[i]]];
			answer[o[i]][l[o[i]]] = t;
			l[o[i]]++;
		}
	}
	allocate_tickets(answer);
	return res;
}

Compilation message (stderr)

tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:42:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |   for (int i = 0; i < o.size() / 2; i++)
      |                   ~~^~~~~~~~~~~~~~
tickets.cpp:48:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |   for (int i = o.size() / 2; i < o.size(); i++)
      |                              ~~^~~~~~~~~~

• 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