Submission #975084

#	Time	Username	Problem	Language	Result	Execution time	Memory
975084		allw	Knapsack (NOI18_knapsack)	C++17	100 / 100	127 ms	8848 KiB

knapsack

#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>

int main() {
    int s, n; std::cin >> s >> n;
    std::vector<std::vector<int>> items(n, std::vector<int>(3));

    // s in [1, 2000]
    for (int i = 0; i < n; ++i) {
        std::cin >> items[i][0] >> items[i][1] >> items[i][2];
        // cost, weight, count
    }

    std::sort(items.begin(), items.end(), std::greater<std::vector<int>>());

    std::vector<std::vector<int>> a(2001, std::vector<int>());
    for (int i = 0; i < n; ++i) {
        int cnt = items[i][2];
        int w = items[i][1];
        int max_items = 2000 / w;

        while (cnt > 0 && a[w].size() < max_items) {
            a[w].push_back(items[i][0]);
            cnt--;
        }
    }

    std::vector<std::vector<int>> items2;
    for (int i = 0; i < a.size(); ++i) {
        for (int j = 0; j < a[i].size(); ++j) {
            items2.push_back({i, a[i][j]});
            // w, cost
        }
    }

    std::vector<int> dp(s + 1, INT_MIN);
    dp[0] = 0;

    for (int i = 0; i < items2.size(); ++i) {
        int w = items2[i][0];
        int c = items2[i][1];
        std::vector<int> new_dp = dp;

        for (int j = 0; j < dp.size(); ++j) {
            if (dp[j] >= 0 && j + w < dp.size()) {
                new_dp[j + w] = std::max(new_dp[j + w], dp[j] + c);
            }
        }

        dp = new_dp;
    }

    int mmax = 0;
    for (int i = 0; i < dp.size(); ++i) {
        mmax = std::max(dp[i], mmax);
    }

    std::cout << mmax << '\n';
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:24:39: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   24 |         while (cnt > 0 && a[w].size() < max_items) {
      |                           ~~~~~~~~~~~~^~~~~~~~~~~
knapsack.cpp:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for (int i = 0; i < a.size(); ++i) {
      |                     ~~^~~~~~~~~~
knapsack.cpp:32:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |         for (int j = 0; j < a[i].size(); ++j) {
      |                         ~~^~~~~~~~~~~~~
knapsack.cpp:41:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |     for (int i = 0; i < items2.size(); ++i) {
      |                     ~~^~~~~~~~~~~~~~~
knapsack.cpp:46:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         for (int j = 0; j < dp.size(); ++j) {
      |                         ~~^~~~~~~~~~~
knapsack.cpp:47:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |             if (dp[j] >= 0 && j + w < dp.size()) {
      |                               ~~~~~~^~~~~~~~~~~
knapsack.cpp:56:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |     for (int i = 0; i < dp.size(); ++i) {
      |                     ~~^~~~~~~~~~~

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