Radix Sort

# LSD
def counting_sort(arr, exp):
    n = len(arr)
    output = [0] * n
    count = [0] * 10

    # count the occurrences
    for i in range(n):
        index = (arr[i] // exp) % 10
        count[index] += 1

    # accumulated with previous
    for i in range(1, 10):
        count[i] += count[i - 1]

    i = n - 1
    while i >= 0:
        index = (arr[i] // exp) % 10
        output[count[index] - 1] = arr[i]
        count[index] -= 1
        i -= 1

    for i in range(n):
        arr[i] = output[i]


def radix_sort(arr):
    max_value = max(arr)
    exp = 1

    # radix sort from low digit to high digit
    while max_value // exp > 0:
        counting_sort(arr, exp)
        exp *= 10


# Example
data = [170, 45, 75, 90, 802, 24, 2, 66]
print("Original:", data)
radix_sort(data)
print("After:", data)
# Original: [170, 45, 75, 90, 802, 24, 2, 66]
# After: [2, 24, 45, 66, 75, 90, 170, 802]