Solution to code fights challenge https://codefights.com/arcade/intro/level-7/PTWhv2oWqd6p4AHB9

code_fights_permutation.py

from itertools import permutations

a = ["aba", "bbb", "bab"]
b = ["ab", "bb", "aa"]
c = ["ab", "bb", "aa", "ab", "bb", "aa", "ab", "bb", "aa", "ab", "bb", "aa"]


def string_diff(x, y):
    stuff = sum(1 for x, y in zip(x, y) if x != y)
    return stuff


def compare_elements(arrangement):
    i = 0
    global counter
    while i < len(arrangement)-1:
        x = arrangement[i]
        y = arrangement[i+1]
        num_diff = string_diff(x,y)
        counter += 1
        if num_diff > 1:
            return False
        #print(x, y, num_diff)
        i += 1
    return True


def compare_permutations(input_array):
    for arrangement in permutations(input_array):
        if compare_elements(arrangement) is True:
            return True
    return False


counter = 0
compare_permutations(a), counter

counter = 0
compare_permutations(b), counter

counter = 0
compare_permutations(c), counter