प्रोग्राम की सुविधाएँ · शब्दकोशीय रैंक से क्रमचय

from math import factorial
def unrank_permutation(size, rank):
    if type(size) is not int or not 0 <= size <= 10:
        raise ValueError("size 0 through 10")
    if type(rank) is not int or not 0 <= rank < factorial(size):
        raise ValueError("rank outside permutation count")
    available, result = list(range(size)), []
    for remaining in range(size,0,-1):
        index, rank = divmod(rank, factorial(remaining-1))
        result.append(available.pop(index))
    return result