Code:
/**
** Java Program to Implement Knapsack Algorithm
**/
import java.util.Scanner;
/** Class Knapsack **/
public class Knapsack
{
public void solve(int[] wt, int[] val, int W, int N)
{
int NEGATIVE_INFINITY = Integer.MIN_VALUE;
int[][] m = new int[N + 1][W + 1];
int[][] sol = new int[N + 1][W + 1];
for (int i = 1; i <= N; i++)
{
for (int j = 0; j <= W; j++)
{
int m1 = m[i - 1][j];
int m2 = NEGATIVE_INFINITY;
if (j >= wt[i])
m2 = m[i - 1][j - wt[i]] + val[i];
/** select max of m1, m2 **/
m[i][j] = Math.max(m1, m2);
sol[i][j] = m2 > m1 ? 1 : 0;
}
}
/** make list of what all items to finally select **/
int[] selected = new int[N + 1];
for (int n = N, w = W; n > 0; n--)
{
if (sol[n][w] != 0)
{
selected[n] = 1;
w = w - wt[n];
}
else
selected[n] = 0;
}
/** Print finally selected items **/
System.out.println("\nItems selected : ");
for (int i = 1; i < N + 1; i++)
if (selected[i] == 1)
System.out.print(i +" ");
System.out.println();
}
/** Main function **/
public static void main (String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Knapsack Algorithm Test\n");
/** Make an object of Knapsack class **/
Knapsack ks = new Knapsack();
System.out.println("Enter number of elements ");
int n = scan.nextInt();
int[] wt = new int[n + 1];
int[] val = new int[n + 1];
System.out.println("\nEnter weight for "+ n +" elements");
for (int i = 1; i <= n; i++)
wt[i] = scan.nextInt();
System.out.println("\nEnter value for "+ n +" elements");
for (int i = 1; i <= n; i++)
val[i] = scan.nextInt();
System.out.println("\nEnter knapsack weight ");
int W = scan.nextInt();
ks.solve(wt, val, W, n);
}
}
Output:
Knapsack Algorithm Test
Enter number of elements
5
Enter weight for 5 elements
50 10 20 40 30
Enter value for 5 elements
300 60 90 100 240
Enter knapsack weight
60
Items selected :
2 3 5
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