PPER-Partial Permutations.py

"""
	Rosalind Problems: Partial Permutations

	Problem ID: PPER

	http://rosalind.info/problems/pper/

	A partial permutation is an ordering of only k objects taken from a collection containing n objects (i.e., k≤n). For example, one partial permutation of three of the first eight positive integers is given by (5,7,2).

	The statistic P(n,k) counts the total number of partial permutations of k objects that can be formed from a collection of n objects. Note that P(n,n) is just the number of permutations of n objects, which we found to be equal to n!=n(n−1)(n−2)⋯(3)(2) in “Enumerating Gene Orders”.

	Given: Positive integers n and k such that 100≥n>0 and 10≥k>0.

	Return: The total number of partial permutations P(n,k), modulo 1,000,000.
"""

def fac(x):
	if x==1:
		return x
	else:
		return x*fac(x-1)

n = 90
k = 9

perm = fac(n)/fac(n-k)
perm = perm % 1000000
print(int(perm))
print(perm)