CODEWITHSUNDEEP
pythonalgorithmgreedy
akshay koli
akshay koli

Reputation: 311

python program give error(fraction knapsack problem)

fraction knapsack problem with python it gives an error when i'm running the code, is the split function is not working for the integer values.

Traceback (most recent call last):
  File "C:/Users/Akshay/Desktop/python/kapsack_problem.py", line 49, in <module>
    .format(n)).split()
  File "<string>", line 1
    60 100 120
         ^
SyntaxError: invalid syntax

Here is the source code of a Python program to solve the fractional knapsack problem using greedy algorithm. what i'm doing wrong please tell me. thanks in advance.

def fractional_knapsack(value, weight, capacity):

    index = list(range(len(value)))
    # contains ratios of values to weight
    ratio = [v/w for v, w in zip(value, weight)]
    # index is sorted according to value-to-weight ratio in decreasing order
    index.sort(key=lambda i: ratio[i], reverse=True)

    max_value = 0
    fractions = [0]*len(value)
    for i in index:
        if weight[i] <= capacity:
            fractions[i] = 1
            max_value += value[i]
            capacity -= weight[i]
        else:
            fractions[i] = capacity/weight[i]
            max_value += value[i]*capacity/weight[i]
            break

    return max_value, fractions


n = int(input('Enter number of items: '))
value = input('Enter the values of the {} item(s) in order: '
              .format(n)).split()
value = [int(v) for v in value]
weight = input('Enter the positive weights of the {} item(s) in order: '
               .format(n)).split()
weight = [int(w) for w in weight]
capacity = int(input('Enter maximum weight: '))

max_value, fractions = fractional_knapsack(value, weight, capacity)
print('The maximum value of items that can be carried:', max_value)
print('The fractions in which the items should be taken:', fractions)

Upvotes: 2

Views: 614

Answers (1)

m.raynal
m.raynal

Reputation: 3123

It seems that you try to run this code with a Python 2.x interpreter, while your code is written in Python 3. In order to be able to run it, you need to check that Python 3 is installed on your machine (see here for installations instructions).
To run it, run 

python3 my_script.py

in a terminal.
Another possiblity is to paste

#!/usr/bin/env python3

at the top of your python script. Then if you make the file executable (by running chmod +x myscript.py on ubuntu for instance), you can then run it simply with

./my_script.py

Upvotes: 1

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