LEXF-Enumerating k-mers Lexicographically.py

"""
	Rosalind Problems: Enumerating k-mers Lexicographically

	Problem ID: LEXF

	http://rosalind.info/problems/lexf/

	Assume that an alphabet A has a predetermined order; that is, we write the alphabet as a permutation A=(a1,a2,…,ak), where a1<a2<⋯<ak. For instance, the English alphabet is organized as (A,B,…,Z).

	Given two strings s and t having the same length n, we say that s precedes t in the lexicographic order (and write s<Lext) if the first symbol s[j] that doesn't match t[j] satisfies sj<tj in A.

	Given: A collection of at most 10 symbols defining an ordered alphabet, and a positive integer n (n≤10).

	Return: All strings of length n that can be formed from the alphabet, ordered lexicographically (use the standard order of symbols in the English alphabet).
"""

import itertools

with open("hello.fasta", 'r') as f:
    string = f.readline().split()
    n = int(f.readline().strip())
    result = list(itertools.product(string, repeat = n))
    #print(result)
    print("\n".join(["".join(x) for x in result]))

#Code source: https://github.com/zonghui0228/Rosalind-Solutions/blob/master/code/rosalind_lexf.py