Please Help!

[bntayfur]

I tried so many times but i couldn't do it :(
The steps are all below, someone please help me!

Algorithm 1 Greedy Algorithm for the Continuous Knapsack Problem
1: Input: n items with size si, value vi
2: Input: Knapsack capacity K
3: Set solution vector x equal to 0 for all xi
4: Set current objective function value z = 0
5: Calculate ri =vi/si for all items i = 1, . . . , n
6: Sort the ri values in non-increasing order, place in vector R
7: Set u, representing the used knapsack capacity, to zero
8: Set iterator i to 1
9: while u < K do
10: if si + u ≤ K then
11: Set xi = 1
12: Set u = u + si
13: Set z = z + vi
14: else if si + u > K then
15: Set xi
to the maximum amount of item i that can be placed in the knapsack
16: Set u = u + sixi
(Note, this should equal K)
17: Set z = z + vixi
18: end if
19: Set i = i + 1
20: end while
21: Return the solution vector x and objective function value z

[scidam]

This is almost a valid Python program. What did you try so far?
It seems that you need a bit of effort to turn this algorithm into working program.

[bntayfur]

def knapSack(K,s,v,n):
    z=0
    u=0
    listx=[]
    R=[]
    for k in s:
        m=v[k]
        r= m/k
        R.append(r)
        R.sort()
        if s.index(k)== len(s)-1:
            R.reverse()
    
        if  k + u <= K: 
            x = 1
            u = u + k
            z = z + m
                    
        elif k + u > K:
            x=0
            u = K
            z = z + m*x
        listx.append(x)
       
    print(x)
    print(z)   
    

# To test above function 
v = [60, 100, 120] 
s = [10, 20, 30] 
K = 50
n = len(v)
knapSack(K,s,v,n)

def knapSack(K,s,v,n):
    z=0
    u=0
    i=1
    listx=[]
    R=[]
    for k in s:
        m=v[k]
        r= m/k
        R.append(r)
        R.sort()
        if s.index(k)== len(s)-1:
            R.reverse()
    
        while i <= n: 
            if  k + u <= K: 
                x = 1
                u = u + k
                z = z + m
                    
            elif k + u > K:
                x=0
                u = K
                z = z + m*x
            listx.append(x)
        i = i + 1
    
    print(x)
    print(z)   
    
   
# To test above function 
v = [60, 100, 120] 
s = [10, 20, 30] 
K = 50
n = len(v)
knapSack(K,s,v,n)

2 things i tried so far, gone wrong, i don't know python so couldn't really figure out :(

[bntayfur]

1: Input: n items with size si,value vi
2: Input: Knapsack capacity K
3: Set solution vector x equal to 0 for all xi
4: Set current objective function value z = 0
5: Calculate ri =vi/si for all items i = 1, . . . , n
6: Sort the ri values in non-increasing order, place in vector R
7: Set u, representing the used knapsack capacity, to zero
8: Set iterator i to 1
9: while u < K do
10: if si + u ≤ K then
11: Set xi = 1
12: Set u = u + si
13: Set z = z + vi
14: else if si + u > K then
15: Set xi
to the maximum amount of item i that can be placed in the knapsack
16: Set u = u + sixi
(Note, this should equal K)
17: Set z = z + vixi
18: end if
19: Set i = i + 1
20: end while
21: Return the solution vector x and objective function value z

def knapSack(K,s,v,n):
    z=0
    u=0
    i=1
    listx=[]
    R=[]
    for k in s:
        m=v[k]
        r= m/k
        R.append(r)
        R.sort()
        if s.index(k)== len(s)-1:
            R.reverse()
    
        while i <= n: 
            if  k + u <= K: 
                x = 1
                u = u + k
                z = z + m
                    
            elif k + u > K:
                x=0
                u = K
                z = z + m*x
            listx.append(x)
        i = i + 1
    
    print(x)
    print(z)   
    
   
# To test above function 
v = [60, 100, 120] 
s = [10, 20, 30] 
K = 50
n = len(v)
knapSack(K,s,v,n)

What's wrong someone help me please not good with python :(

[ibreeden]

Is this the error you get?

Error:
Traceback (most recent call last):
  File "/home/ibreeden/PycharmProjects/kanweg/hello.py", line 37, in <module>
    knapSack(K, s, v, n)
  File "/home/ibreeden/PycharmProjects/kanweg/hello.py", line 8, in knapSack
    m = v[k]
IndexError: list index out of range

It would be helpful if you would provide the errormessage yourself.
The message is quite clear. In line 8 you try to assign v[k] and the index (k) is out of range.
"v" is a list of 3 elements:

v = [60, 100, 120]

So you can only access: v[0], v[1] and v[2]

"k" gets te values of "for k in s". "s" has the values:

s = [10, 20, 30]

So in the first loop "k" gets the value 10. Then v[10] will be accessed which is impossible because only access v[0], v[1] and v[2].
That is the error you get.