Algoritmia - Mergesort sin recursión??

def merge(arr, l, m, r):

    n1 = m - l + 1

    n2 = r - m

    L = [arr[l + i] for i in range(n1)]

    R = [arr[m + 1 + i] for i in range(n2)]

    i = j = 0

    k = l

    while i < n1 and j < n2:

        if L <= R[j]:

            arr[k] = L[i]

            i += 1

        else:

            arr[k] = R[j]

            j += 1

        k += 1

    while i < n1:

        arr[k] = L[i]

        i += 1

        k += 1

    while j < n2:

        arr[k] = R[j]

        j += 1

        k += 1

def merge_sort(arr):

    stack = []

    n = len(arr)

    for size in range(1, n):

        for left in range(0, n - 1, 2 * size):

            mid = min(left + size - 1, n - 1)

            right = min(left + 2 * size - 1, n - 1)

            merge(arr, left, mid, right)

    return arr

# Ejemplo de uso

arr = [38, 27, 43, 3, 9, 82, 10]

sorted_arr = merge_sort(arr.copy())

print("Arreglo original:", arr)

print("Arreglo ordenado:", sorted_arr)