"""
This is an implementation of Pigeon Hole Sort.
For doctests run following command:
python3 -m doctest -v pigeon_sort.py
or
python -m doctest -v pigeon_sort.py
For manual testing run:
python pigeon_sort.py
"""
from typing import List
def pigeon_sort(array: List[int]) -> List[int]:
"""
Implementation of pigeon hole sort algorithm
:param array: Collection of comparable items
:return: Collection sorted in ascending order
>>> pigeon_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> pigeon_sort([])
[]
>>> pigeon_sort([-2, -5, -45])
[-45, -5, -2]
"""
if len(array) == 0:
return array
_min, _max = min(array), max(array)
holes_range = _max - _min + 1
holes, holes_repeat = [0] * holes_range, [0] * holes_range
for i in array:
index = i - _min
holes[index] = i
holes_repeat[index] += 1
index = 0
for i in range(holes_range):
while holes_repeat[i] > 0:
array[index] = holes[i]
index += 1
holes_repeat[i] -= 1
return array
if __name__ == "__main__":
import doctest
doctest.testmod()
user_input = input("Enter numbers separated by comma:\n")
unsorted = [int(x) for x in user_input.split(",")]
print(pigeon_sort(unsorted))