https://www.hackerrank.com/challenges/alphabet-rangoli

alphabet-rangoli.py

def print_rangoli(size):
    ascii_lowercase = 'abcdefghijklmnopqrstuvwxyz' # from string import ascii_lowercase
    width = size*4-3
    chars = ascii_lowercase[:size]

    #for line in range(1,size+1):
    #    line_chars = chars[size-1:size-line:-1] + chars[-line:]
    #    print(('-'.join(line_chars)).center(width, '-'))
    #for line in reversed(range(1,size)):
    #    line_chars = chars[size-1:size-line:-1] + chars[-line:]
    #    print(('-'.join(line_chars)).center(width, '-'))
    
    #lines = [None] * (size*2-1)
    #for i in range(size):
    #    lines[size+i-1] = chars[i:][:0:-1] + chars[i:]
    #lines[:size-1] = lines[:size-1:-1]
    #print(*[('-'.join(line)).center(width, '-') for line in lines], sep='\n')
    
    #lines = [None] * (size*2-1)
    #lines[size-1:] = [chars[i:][:0:-1] + chars[i:] for i in range(size)]
    #lines[:size-1] = lines[:size-1:-1]
    #print(*[('-'.join(line)).center(width, '-') for line in lines], sep='\n')
    
    #lines = [None] * (size*2-1)
    #lines[:size] = [chars[size-1-i:][:0:-1] + chars[size-1-i:] for i in range(size)]
    #lines[size:] = lines[size-2::-1]
    #print(*[('-'.join(line)).center(width, '-') for line in lines], sep='\n')
    
    #from itertools import chain
    #lines = (chars[size-1-i:][:0:-1] + chars[size-1-i:] for i in chain(range(size), range(size-2,-1,-1)))
    #print(*[('-'.join(line)).center(width, '-') for line in lines], sep='\n')

    #lines = (chars[size-1-i:][:0:-1] + chars[size-1-i:] for j in (range(size), range(size-2,-1,-1)) for i in j)
    #print(*[('-'.join(line)).center(width, '-') for line in lines], sep='\n')

    #print(*[('-'.join(line)).center(width, '-') for line in (chars[size-1-i:][:0:-1] + chars[size-1-i:] for j in (range(size), range(size-2,-1,-1)) for i in j)], sep='\n')

    print(*[('-'.join(chars[size-1-i:][:0:-1] + chars[size-1-i:])).center(width, '-') for j in (range(size), range(size-2,-1,-1)) for i in j], sep='\n')
    
if __name__ == '__main__':
    n = int(input())
    print_rangoli(n)