Submission #746398

#	Time	Username	Problem	Language	Result	Execution time	Memory
746398		JasonTaiwan	Knapsack (NOI18_knapsack)	C++14	100 / 100	168 ms	5068 KiB

knapsack

#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
using namespace std;

struct item {
    long long weight;
    long long worth;
    long long cnt;
};

bool comp(item i1, item i2) {
    if (i1.weight == i2.weight) {
        return (i1.worth > i2.worth);
    }
    return (i1.weight < i2.weight);
}

int main() {
    long long S, N;
    long long cnt;
    cin >> S >> N;
    vector < item > items;
    for (int i = 0; i < N; i++) {
        long long wei, wor;
        cin >> wor >> wei;
        cin >> cnt;
        items.push_back({wei, wor, cnt});
    }
    
    sort(items.begin(), items.end(), comp);
    vector < item > new_item;
    map < int, int > myMap;
    for (auto i: items) {
        if (myMap[i.weight] * i.weight > S) {
            continue;
        }
        myMap[i.weight] += i.cnt;
        new_item.push_back(i);
    }
    swap(new_item, items); // new_item是去掉重複的
    long long dp[S + 1] = {0};
    
    for (int i = 0; i < items.size(); i++) {
        for (int j = S; j >= 0; j--) {
            int cntr = 0;
            while (cntr * items[i].weight <= j && cntr <= items[i].cnt) {
                dp[j] = max(dp[j], dp[j - cntr * items[i].weight] + cntr * items[i].worth);
                cntr++;
            }
        }
    }
    cout << dp[S] << endl;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:45:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<item>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |     for (int i = 0; i < items.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~

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