recursive_split.py

# Break this string of numbers into a sequence of 1 digit and 2 digit numbers without changing their relative order.
# Input : 1234
# Output : {1,2,34} {1,23, 4} {1,2,3,4} {12,34} {12,3,4}

def recursive_split(seq: str) -> tuple:
    # check for valid strings
    if not seq or len(seq) == 0:
        result =  [()]
    # base case
    elif len(seq) == 1:
        result = [(seq, )]
    # recursive case
    else:
        prefix = (seq[0], )
        result = [prefix + rest for rest in recursive_split(seq[1:])]
        prefix = (seq[0:2], )
        result += [prefix + rest for rest in recursive_split(seq[2:])]
    return result

# tests
print(recursive_split(False))
print(recursive_split('a'))
print(recursive_split('1234'))
print(recursive_split('abcdef'))