Create an alphabet rangoli hacker rank challenge

create_rangoli.py

import string

def next_less_even_number(n):
    for i in range(n-1, 0, -1):
        if i % 2 == 0:
            return i

def next_greater_even_number(n, x=2):
    return n + (x-n %x)

def print_rangoli(size):
    n = size
    first_n_chars = string.ascii_lowercase[:n]
    s_parts = []
    width = (n * 2) -1
    next_less_even = next_less_even_number(n*2)
    next_greater_even = next_greater_even_number(0)

    for i in range(1, width+1):
        if i < n:
            part_1 = '-'*next_less_even
            part_3 = '-'*next_less_even
            chars_to_use = first_n_chars[n - i :]
            mid_char = chars_to_use[len(chars_to_use)//2]
            part_2 = mid_char
            if len(chars_to_use) > 1:
                sub_part_2b = '-'.join(i for i in chars_to_use)
                sub_part_2a = '-'.join(i for i in reversed(chars_to_use))
                sub_part_2a = sub_part_2a[:-1] # Remove last char
                part_2 = sub_part_2a + sub_part_2b
            next_less_even = next_less_even_number(next_less_even)
        elif i == n:
            chars_to_use = first_n_chars
            part_1 = '-'.join(i for i in reversed(chars_to_use))
            part_1 = part_1[:-1] # Remove lats char since it starts part 2
            part_2 = '-'.join(i for i in chars_to_use)
            part_3 = ''
        elif i > n:
            part_1 = '-'*next_greater_even
            part_3 = '-'*next_greater_even
            chars_to_use = first_n_chars[i-n:]
            mid_char = chars_to_use[len(chars_to_use)-1:]
            part_2 = mid_char
            if len(chars_to_use) < n:
                sub_part_2a = '-'.join(i for i in reversed(chars_to_use))
                sub_part_2a = sub_part_2a[:-1] # Remove last char
                sub_part_2b = '-'.join(i for i in chars_to_use)
                part_2 = sub_part_2a + sub_part_2b

            next_greater_even = next_greater_even_number(next_greater_even)
        s = part_1 + part_2 + part_3
        s_parts.append(s)

    print('\n'.join(s for s in s_parts))

if __name__ == '__main__':
    n = int(input())
    print_rangoli(n)

In [425]: make_rangoli(11)
--------------------k--------------------
------------------k-j-k------------------
----------------k-j-i-j-k----------------
--------------k-j-i-h-i-j-k--------------
------------k-j-i-h-g-h-i-j-k------------
----------k-j-i-h-g-f-g-h-i-j-k----------
--------k-j-i-h-g-f-e-f-g-h-i-j-k--------
------k-j-i-h-g-f-e-d-e-f-g-h-i-j-k------
----k-j-i-h-g-f-e-d-c-d-e-f-g-h-i-j-k----
--k-j-i-h-g-f-e-d-c-b-c-d-e-f-g-h-i-j-k--
k-j-i-h-g-f-e-d-c-b-a-b-c-d-e-f-g-h-i-j-k
--k-j-i-h-g-f-e-d-c-b-c-d-e-f-g-h-i-j-k--
----k-j-i-h-g-f-e-d-c-d-e-f-g-h-i-j-k----
------k-j-i-h-g-f-e-d-e-f-g-h-i-j-k------
--------k-j-i-h-g-f-e-f-g-h-i-j-k--------
----------k-j-i-h-g-f-g-h-i-j-k----------
------------k-j-i-h-g-h-i-j-k------------
--------------k-j-i-h-i-j-k--------------
----------------k-j-i-j-k----------------
------------------k-j-k------------------
--------------------k--------------------