Submission #1218639

#	Time	Username	Problem	Language	Result	Execution time	Memory
1218639		pauloaph	Knapsack (NOI18_knapsack)	C++20	17 / 100	1 ms	328 KiB

knapsack

#include<iostream>
#include<algorithm>
#include <cmath>
using namespace std;

const int MAXN =  100000;
const int MAXC = 1000;

int main(){

    int C;
    int n;

    cin >> C >> n;

    int V[n];
    int W[n];
    long int B[n];
    

    for (int i = 0; i < n; i++){
        cin >> V[i] >> W[i] >> B[i];
    }

    vector<long> NW, NV;
    long int M = 0;


    // vamos criar os novos itens (pacotes)
    for ( int i = 0; i < n; ++i ){
        int pos = 0;
        // procuramos o bit mais significativo
        while ( (1 << pos) < B[i] )

            pos++;
        // aqui sabemos que (2 ^ pos) >= B[i]
        pos--;
        // agora 2 ^ pos < B[i], logo (2 ^ pos) - 1 <= B[i] 
        while ( pos >= 0 ){
            NW.push_back((1LL << pos) * W[i]);
            NV.push_back((1LL << pos) * V[i]);
            B[i] -= (1 << pos);
            M++;
            pos--;
        }
        if ( B[i] ){ // se sobrou um resto
            NW.push_back(B[i] * W[i]);
            NV.push_back(B[i] * V[i]);
            M++;
            B[i] = 0;
        }
    }

    long int dp[2][C+1];
    int prev = 0, act = 1;
    // caso base : quando nao temos mais itens
    for ( int c = 0; c <= C; ++c )
        dp[prev][c] = 0;


    for ( int i = M - 1; i >= 0; --i ){
        for ( int c = 0; c <= C; ++c ){
            dp[act][c] = dp[prev][c];
            if ( NW[i] <= c ) {
                dp[act][c] = max( dp[act][c], dp[prev][c - NW[i]] + NV[i] );
            }
        }
        swap( act, prev );
    }
      
   cout << dp[prev][C] << endl;
   return 0;
}

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