Submission #1082805

#	Time	Username	Problem	Language	Result	Execution time	Memory
1082805		1tejasjain	Knapsack (NOI18_knapsack)	C++17	100 / 100	55 ms	5488 KiB

knapsack

#include<bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
//By Tejas India, https://www.linkedin.com/in/1tejasjain/
// void call(){
//     int s, n;  cin>>s>>n;
//     vector<int> maxValueByWeight(s+1, 0);
//     maxValueByWeight[0] = 0;
//     for(int item=1; item<=n; item++){
//         int value, weight, quantity; cin>>value>>weight>>quantity;
//         // cout<<"Item: "<<item<<endl;
//         for(int i=1; i<=quantity; i++)
//             for(int ks = s; ks>=0; ks--){
//                     if(ks-weight>=0)
//                         maxValueByWeight[ks] = max(maxValueByWeight[ks], maxValueByWeight[ks-weight]+value);
//                 // cout<<ks<<": "<<maxValueByWeight[ks]<<" ";
//             }
//         // cout<<endl;
//     }
//     cout<<maxValueByWeight[s]<<endl;
// }
void call(){
    int s, n;  cin>>s>>n;
    vector<int> maxValueByWeight(s+1, 0);
    maxValueByWeight[0] = 0;
    map<int, vector<pair<int, int>>> byWeight;

    for(int item=1; item<=n; item++){
        int value, weight, quantity; cin>>value>>weight>>quantity;
        byWeight[weight].push_back({value, quantity});
    }

    for(auto [weight, vec]: byWeight){
        sort(vec.begin(), vec.end(), greater<pair<int, int>>());
        for(int ks = s; ks>=0; ks--){
			int copies = 0;
			int type_at = 0;
			int curr_used = 0;
			long long profit = 0;
			// go through as many items until we run out of items or usable
			// weight
			while ((copies + 1) * weight <= ks && type_at < vec.size()) {
				copies++;
				profit += vec[type_at].first;
				if (maxValueByWeight[ks - copies * weight] != INT32_MIN) {
					maxValueByWeight[ks] = max(maxValueByWeight[ks], maxValueByWeight[ks - copies * weight] + profit);
				}

				curr_used++;
				if (curr_used == vec[type_at].second) {
					curr_used = 0;
					type_at++;
				}
			}

            // for(auto [value, quantity]: vec){
            //     for(int i=1; i<=quantity; i++){
            //             if(ks-weight>=0)
            //                 maxValueByWeight[ks] = max(maxValueByWeight[ks], maxValueByWeight[ks-weight]+value);
            //         // cout<<ks<<": "<<maxValueByWeight[ks]<<" ";
            //     }
            //     // cout<<endl;
            // }



        }
    }
    cout<<maxValueByWeight[s]<<endl;
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll t=1;
    //cin>>t;
    while(t--){
        call();
    }
    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'void call()':
knapsack.cpp:43:50: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |    while ((copies + 1) * weight <= ks && type_at < vec.size()) {
      |                                          ~~~~~~~~^~~~~~~~~~~~

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