Add unbounded_knapsack.py

[kenzonobre]

Describe your change:

Add unbounded knapsack algorithm, which is an extension of the 0-1 knapsack problem.

0-1 Knapsack Problem :
https://en.wikipedia.org/wiki/Knapsack_problem
https://www.geeksforgeeks.org/0-1-knapsack-problem-dp-10/

Unbounded knapsack :
https://www.geeksforgeeks.org/unbounded-knapsack-repetition-items-allowed/

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[kenzonobre]

@cclauss could you please review my code? I could work on it more if necessary, but I think it looks good

[CaedenPH]

Looks good to me, but I'm sure Cclauss will find some problems ;)

[kenzonobre]

@cclauss could you please review my code? I could work on it more if necessary, but I think it looks good

[cclauss]

• How is this different than all our other knapsack algorithms?
• Is it faster? Can we prove that with a benchmark?
• How is this algorithm unbound if the first parameter is capacity?
• Please add a test that demonstrates how would this unbound algorithm would deal with weights and values that were never-ending cycles? https://docs.python.org/3/library/itertools.html#itertools.cycle

[cclauss]

Suggested change

	for i in range(n):
	# weight of the i-th item
	weight = items_weights[i]
	# value of the i-th item
	value = items_values[i]
	for weight, value in zip(weights, values):

[cclauss]

Not needed with zip().

Suggested change

	# n is the number of items
	n = len(items_weights)

[cclauss]

What does dp stand for? Please make the code more self documenting by expanding the acronym.

Suggested change

	dp = [0 for x in range(capacity + 1)]
	dp = [0] * (capacity + 1)

[cclauss]

Suggested change

	>>> c = 70
	>>> items_values = [40, 900, 120]
	>>> items_weights = [10, 20, 30]
	>>> knapsack(c, items_weights, items_values)
	>>> knapsack(capacity=70, weights=(40, 900, 120), values=(10, 20, 30))

Please repeat for the other tests.

Please add tests for:
capacity = 0
capacity - -5
len(values) != len(weights)
len(values) == 5 and len(weights) == 0
etc.

[cclauss]

Suggested change

	def knapsack(capacity: int, items_weights: list[int], items_values: list[int]) -> int:
	def knapsack(capacity: int, weights: list[int], values: list[int]) -> int: