Given two numbers n and r, the task is to find the value of nPr.
nPr represents n permutation r which is calculated as n!/(n-k)!. Permutation refers to the process of arranging all the members of a given set to form a sequence. The number of permutations on a set of n elements is given by n!, where “!” represents factorial.
nPr = n! / (n - r)!
Optimization for multiple queries of nPr
If there are multiple queries for nPr, we may precompute factorial values and use same for every call. This would avoid computation of same factorial values again and again.
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the “Improve Article” button below.
Be the First to upvote.
Please write to us at email@example.com to report any issue with the above content.