Python Program to Generate Gray Codes using Recursion

def get_gray_codes(n):
    """Return n-bit Gray code in a list."""
    if n == 0:
        return ['']
    first_half = get_gray_codes(n - 1)
    second_half = first_half.copy()
 
    first_half = ['0' + code for code in first_half]
    second_half = ['1' + code for code in reversed(second_half)]
 
    return first_half + second_half
 
 
n = int(input('Enter the number of bits: '))
codes = get_gray_codes(n)
print('All {}-bit Gray Codes:'.format(n))
print(codes)

Output

Enter the number of bits: 3
All 3-bit Gray Codes:
['000', '001', '011', '010', '110', '111', '101', '100']