Digits and Operators problem

digits.py

from collections import OrderedDict

DIGITS: str = '123456789'
TARGET: int = 101
OPCODE = OrderedDict([
    ('0', ''),
    ('1', '*'),
    ('2', '-'),
    ('3', '+'),
])
COUNT: int = len(DIGITS)
BASE: int = len(OPCODE.keys())
LIMIT: str = list(OPCODE.keys())[-1] * (COUNT - 1)

def number_to_base(n: int, b: int) -> str:
    if n == 0:
        return '0'
    digits = []
    while n:
        digits.append(int(n % b))
        n //= b
    return ''.join(str(d) for d in digits[::-1])

def interlace_ops_to_digits(ops: str, digits: str) -> str:
    assert len(ops) == len(digits) - 1
    operations = [OPCODE[op] for op in ops] + ['']
    expression = [val for pair in zip(digits, operations) for val in pair]
    return ''.join(expression)


x: int = 0
solutions = []
while True:
    ops = number_to_base(x, BASE).rjust(COUNT - 1, '0')
    expr = interlace_ops_to_digits(ops, DIGITS)
    result = eval(expr)

    message = f"Operations {ops}: {expr} = {result}"
    if result == TARGET:
        solutions.append(message)
        message += " EVRIKA !!!"
    print(message)

    if ops == LIMIT:
        print("All combinations were executed")
        break
    else:
        x = x + 1

if len(solutions) > 0:
    print("The following solutions were identified")
    for sol in solutions:
        print(sol)
else:
    print("No solution found !")