mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
c909da9b08
* pre-commit: Upgrade psf/black for stable style 2023 Updating https://github.com/psf/black ... updating 22.12.0 -> 23.1.0 for their `2023 stable style`. * https://github.com/psf/black/blob/main/CHANGES.md#2310 > This is the first [psf/black] release of 2023, and following our stability policy, it comes with a number of improvements to our stable style… Also, add https://github.com/tox-dev/pyproject-fmt and https://github.com/abravalheri/validate-pyproject to pre-commit. I only modified `.pre-commit-config.yaml` and all other files were modified by pre-commit.ci and psf/black. * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
"""
|
|
https://en.wikipedia.org/wiki/Combination
|
|
"""
|
|
from math import factorial
|
|
|
|
|
|
def combinations(n: int, k: int) -> int:
|
|
"""
|
|
Returns the number of different combinations of k length which can
|
|
be made from n values, where n >= k.
|
|
|
|
Examples:
|
|
>>> combinations(10,5)
|
|
252
|
|
|
|
>>> combinations(6,3)
|
|
20
|
|
|
|
>>> combinations(20,5)
|
|
15504
|
|
|
|
>>> combinations(52, 5)
|
|
2598960
|
|
|
|
>>> combinations(0, 0)
|
|
1
|
|
|
|
>>> combinations(-4, -5)
|
|
...
|
|
Traceback (most recent call last):
|
|
ValueError: Please enter positive integers for n and k where n >= k
|
|
"""
|
|
|
|
# If either of the conditions are true, the function is being asked
|
|
# to calculate a factorial of a negative number, which is not possible
|
|
if n < k or k < 0:
|
|
raise ValueError("Please enter positive integers for n and k where n >= k")
|
|
return factorial(n) // (factorial(k) * factorial(n - k))
|
|
|
|
|
|
if __name__ == "__main__":
|
|
print(
|
|
"The number of five-card hands possible from a standard",
|
|
f"fifty-two card deck is: {combinations(52, 5)}\n",
|
|
)
|
|
|
|
print(
|
|
"If a class of 40 students must be arranged into groups of",
|
|
f"4 for group projects, there are {combinations(40, 4)} ways",
|
|
"to arrange them.\n",
|
|
)
|
|
|
|
print(
|
|
"If 10 teams are competing in a Formula One race, there",
|
|
f"are {combinations(10, 3)} ways that first, second and",
|
|
"third place can be awarded.",
|
|
)
|