Diamond2026-04-19

My Solution: Exercism Diamond solution

Instructions

Generate a diamond shape from a given uppercase letter.

The diamond is centered, symmetrical, and built from lines of letters with spaces between repeated characters. The first and last rows contain only A. The widest row contains the target letter twice, with all letters between the top and bottom mirrored around the center.

Example for C:

A B B C C B B A

Solution

def rows(letter):
    n = ord(letter) - ord('A')
    top_half = []

    for i in range(n+1):
        char = chr(ord('A') + i)
        outer_space = ' ' * (n-i)

        if i == 0:
            row = outer_space + char + outer_space
        else:
            inner_space = ' ' * (2 * i - 1)
            row = outer_space + char + inner_space + char + outer_space    

        top_half.append(row)


    return top_half + top_half[:-1][::-1]

Mental Model

Build the top half from A up to the requested letter, then mirror that list without the last row to form the bottom half.