Submission #703198

#	Time	Username	Problem	Language	Result	Execution time	Memory
703198		borisAngelov	Knapsack (NOI18_knapsack)	C++17	100 / 100	98 ms	35184 KiB

knapsack

#include <iostream>
#include <algorithm>
#include <vector>
#include <map>

using namespace std;

int limit, n;

const int inf = 2000000000;

map<int, vector<pair<int, int>>> by_weight;

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> limit >> n;

    for (int i = 1; i <= n; ++i)
    {
        int w, val, copies;

        cin >> val >> w >> copies;

        if (w <= limit)
        {
            by_weight[w].push_back(make_pair(val, copies));
        }
    }

    vector<vector<long long>> dp(by_weight.size() + 1, vector<long long>(limit + 1, -inf));

    dp[0][0] = 0;

    int pos = 1;

    for (auto& [w, items] : by_weight)
    {
        sort(items.begin(), items.end(), greater<pair<int, int>>());

        for (int i = 0; i <= limit; ++i)
        {
            dp[pos][i] = dp[pos - 1][i];

            int copies = 0;
            int type_pos = 0;
            int used = 0;

            long long profit = 0;

            while ((copies + 1) * w <= i && type_pos < items.size())
            {
                ++copies;

                profit += items[type_pos].first;

                if (dp[pos - 1][i - copies * w] != -inf)
                {
                    dp[pos][i] = max(dp[pos][i], profit + dp[pos - 1][i - copies * w]);
                }

                ++used;

                if (used == items[type_pos].second)
                {
                    used = 0;
                    ++type_pos;
                }
            }
        }

        ++pos;
    }

    long long ans = -inf;

    for (int i = 0; i <= limit; ++i)
    {
        ans = max(ans, dp[by_weight.size()][i]);
    }

    cout << ans << endl;

    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:59:54: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |             while ((copies + 1) * w <= i && type_pos < items.size())
      |                                             ~~~~~~~~~^~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 17 / 17
• Subtask 3: 20 / 20
• Subtask 4: 24 / 24
• Subtask 5: 27 / 27