Skip to content

In place of calculating the factorial several times we can run a loop k times to calculate the combination #10087

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 2 commits into from
Closed

In place of calculating the factorial several times we can run a loop k times to calculate the combination #10087

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
cc5751d
In place of calculating the factorial several times we can run a loop…
SubhranShu2332 Oct 8, 2023
52c9e4b
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Oct 8, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 5 additions & 2 deletions maths/combinations.py
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
"""
https://en.wikipedia.org/wiki/Combination
"""
from math import factorial


def combinations(n: int, k: int) -> int:
Expand Down Expand Up @@ -35,7 +34,11 @@ def combinations(n: int, k: int) -> int:
# 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))
res = 1
for i in range(k):
res = res * (n - i)
res = res // (i + 1)
return res


if __name__ == "__main__":
Expand Down