Submission #492445

#	Time	Username	Problem	Language	Result	Execution time	Memory
492445		Psudora	Knapsack (NOI18_knapsack)	C++17	12 / 100	3 ms	4172 KiB

knapsack

#include <bits/stdc++.h> 
using namespace std;       
#define ll long long 
const int mod = 1000000007; 
const int INF = 1e9; 
const int N = (int)1e5+5; 
vector<int>adj[N]; 

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);  
    // 
    int limit, type_num; cin >> limit >> type_num; 
    map<int, vector<pair<int, int>>>by_weight;
    for(int i = 0; i < type_num; i++){
        int val, weight, amt;
        cin >> val >> weight >> amt;
        if(weight <= limit && amt > 0){
            by_weight[weight].push_back({val, amt});
        }
    } 
    vector<vector<ll>>best(by_weight.size()+1, vector<ll>(limit+1, INT32_MIN));
    best[0][0] = 0;
    int at = 1;
    for(auto& [w, items] :  by_weight){
        sort(items.begin(), items.end(), greater<pair<int, int>>());
        for(int i = 0; i <= limit; i++){
            best[at][i] = best[at-1][i];
            int copies = 0;
            int type_at = 0;
            int cur_used = 0;
            ll profit = 0;
            while((copies+1)*w <= i && type_at < items.size()){
                copies++;
                profit += items[type_at].first;
                if(best[at-1][i-copies*w] != INT32_MIN){
                    best[at][i] = max(best[at-1][i], best[at-1][i-copies*w]+profit);
                }
                cur_used++;
                if(cur_used == items[type_at].second){
                    cur_used = 0;
                    type_at++;
                }
            }
        }
        at++;
    }
    cout << *max_element(best.back().begin(), best.back().end()) <<'\n';
	return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:33:48: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |             while((copies+1)*w <= i && type_at < items.size()){
      |                                        ~~~~~~~~^~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 24
• Subtask 5: 0 / 27