Submission #770788

#	Time	Username	Problem	Language	Result	Execution time	Memory
770788		vgoofficial	Knapsack (NOI18_knapsack)	C++14	100 / 100	58 ms	35028 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
    ios_base::sync_with_stdio(false); 
    cin.tie(0);
    int s,n;
    cin >> s >> n;
    vector<vector<pair<int, int>>> items(s+1);
    for(int i = 0; i < n; i++) {
        int value, weight, number;
        cin >> value >> weight >> number;
        items[weight].push_back(make_pair(value, number));
    }
    for(int i = 1; i <= s; i++) {
        sort(begin(items[i]), end(items[i]), [](const pair<int, int> a, const pair<int, int> b) -> bool{
            return a.first>b.first;
        });
    }
    ll arr[s+1][s+1];
    //arr[a][b]=x: first a weights, b total weight, x max value
    for(int i = 0; i <= s; i ++) {
        for(int j = 0; j <= s; j++) {
            arr[i][j]=0;
        }
    }

    for(int i = 1; i <= s; i++) {
        for(int j = 0; j <= s; j++) {
            arr[i][j]=max(arr[i-1][j], arr[i][j]);
            if(items[i].size()==0) continue;
            int weight = j;
            ll value = arr[i-1][j];
            int itemsUsed = 0;
            int index = 0;
            while(weight+i<=s) {
                itemsUsed++;
                weight+=i;
                value+=items[i][index].first;
                arr[i][weight]=max(arr[i][weight], value);
                if(itemsUsed==items[i][index].second) {
                    itemsUsed=0;
                    index++;
                    if(index==items[i].size()) {
                        break;
                    }
                }
            }
        }
    }
    ll ans = 0;
    for(int i = 0; i <= s; i++) {
        ans=max(ans, arr[s][i]);
    }
    cout << ans << endl;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:44:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |                     if(index==items[i].size()) {
      |                        ~~~~~^~~~~~~~~~~~~~~~~

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