Variable Digit Count Sort.

Θ(n) where n is the total digit count

from random import choices

def countingSort(source:[], digits:[], scope:int) -> []:
    counter = [0]*scope
    amount = len(source)

    for x in digits:
        counter[x] += 1

    for i in range(1, scope):
        counter[i] += counter[i-1]

    destination = [0]*amount

    for i in reversed(range(amount)):
        quantity = digits[i]
        # index = count-1
        destination[counter[quantity]-1] = source[i]
        counter[quantity] -= 1

    return destination

def radixSort(source:[], numOfDigits:int, scope:int)->[]:
    amount = len(source)
    dst = source
    for i in range(numOfDigits):
        digits = []
        for x in dst:
            temp = x // (scope ** i)
            digit = temp % scope
            digits.append(digit)
        dst = countingSort(dst, digits, scope)
    return dst

def digitCountOfFigure(figure:int)->int:
    if figure == 0:
        return 1
    count = 0
    while figure != 0:
        count += 1
        figure //= 10
    return count

def variableDigitCountSort()->[]:
    scope = 10
    amount = 1000
    digits = 3
    src = choices(range(amount), k=amount)
    groups = [[] for _ in range(digits)]

    for x in src:
        groups[digitCountOfFigure(x) - 1].append(x)
        
    dst = []
    for i in range(digits):
        dst += radixSort(groups[i], i+1, scope)
    return dst