Submission #918324

#	Time	Username	Problem	Language	Result	Execution time	Memory
918324		kotnid	Knapsack (NOI18_knapsack)	C++14	100 / 100	38 ms	4956 KiB

knapsack

/* 

knapsack with multiple amount 

-> express as 2^0, 2^1,.... 

*/

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll,ll> pii;

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    ll s, n;
    cin >> s >> n;

    ll dp[s+1];
    memset(dp,0,sizeof dp);

    vector<pii> weight[s+1];

    for(int i=0; i<n; i++){
        ll v, w, k;
        cin >> v >> w >> k;
        weight[w].push_back({v,k});
    }

    for(int i=1; i<=s; i++){
        sort(weight[i].begin(), weight[i].end(), greater<pii>());

        ll cnt = 0;

        for(auto [v,k]:weight[i]){
            cnt += i*k;
            ll c = 1; 
            while(c <= k){
                ll v2 = v*c, w2 = i*c;
                for(int j=s; j>=w2; j--)dp[j] = max(dp[j], dp[j-w2]+v2);
                k -= c;
                c *= 2;
            }
            if(k != 0){
                ll v2 = v*k, w2 = i*k;
                for(int j=s; j>=w2; j--)dp[j] = max(dp[j], dp[j-w2]+v2);
            }
            if(cnt > s)break;
        }
        
    }

    cout << dp[s];
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:38:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   38 |         for(auto [v,k]:weight[i]){
      |                  ^

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