knapsack_dp.cpp

#include <iostream>
using namespace std;

int max(int a, int b) {return (a > b) ? a : b;}

int knapsack(int W, int wt[], int val[], int n)
{
    int i, w;
    int K[n+5][W+5]; // DP table

    for (i=0; i <= n; i++)
    {
        for (w=0; w <= W; w++)
        {
            if (i==0 || w==0)
            {
                K[i][w] = 0;
            }
            else if (wt[i-1] <= w)
            {
                K[i][w] = max(val[i-1] + K[i-1][w - wt[i-1]], K[i-1][w]);
            }
            else
            {
                K[i][w] = K[i-1][w];
            }
        }
    }
    return K[n][W];
}

int main()
{
    int val[] = {60, 100, 120};
    int wt[] = {10, 20, 30};
    int W = 50;
    int n = sizeof(val)/sizeof(val[0]);
    
    printf("0-1 DP knapsack: \n");
    int value = knapsack(W, wt, val, n);
    printf("maximum value: %d\n", value);

    return 0;
}