Understanding a pseudocode of Knapsack in recrusive

Question

int knapsack(i, k){

    if(i=N){

        val= 0; //end of recrusive

        return val;
    }

    if (w[i]>k) // no space anymore

        val= knapsack(i+1, k); 

    else {

        a = knapsack(i+1, k) // i don't take with

        b = knapsack(i+1, k-w[i]) + v[i]; //i take with

        val= max(a,b); 

    } 

    return val;
}

My question is, what is N in this case ? In my Program for variables I have weight, value, maxweight and a LinkedList. Anyone can help me out ? Thanks

The place where you got this code from should have explained that. — Carcigenicate, Jul 04 '17 at 01:13
Unfortunately, there is no accurate explanation for this code where i got. just this comments : // calculates maximum value of the backpack problem with size // k for objects with index i and lower. — Jeryoz Dimitar, Jul 04 '17 at 01:17
it is not even a piece of working Java code. And, is it that hard to properly format your code before posting? — Adrian Shum, Jul 04 '17 at 02:32
its not, its a pseudocode that I'm trying to implement to java using LinkedList and ArrayList — Jeryoz Dimitar, Jul 04 '17 at 03:20

score 0 · Answer 1 · answered Jul 04 '17 at 01:58

0

N is the number of elements in the input array/list. The first recursive call is knapsack(0,k), and each recursive call increments i , until it reaches N and the recursion ends.

answered Jul 04 '17 at 01:58

Eran

387,369
54
702
768

a and b ? what is that ? – Jeryoz Dimitar Jul 04 '17 at 03:16
@JeryozDimitar `a` is the result of the `knapsack` algorithm that doesn't include the i'th element and `b` is the result of the `knapsack` algorithm that includes the i'th element. The max of the two gives you the total result. – Eran Jul 04 '17 at 05:16

Understanding a pseudocode of Knapsack in recrusive

1 Answers1