Python/sorts/radix_sort.py

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"""
This is a pure Python implementation of the radix sort algorithm
Source: https://en.wikipedia.org/wiki/Radix_sort
"""
from __future__ import annotations
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def radix_sort(list_of_ints: list[int]) -> list[int]:
"""
Examples:
>>> radix_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> radix_sort(list(range(15))) == sorted(range(15))
True
>>> radix_sort(list(range(14,-1,-1))) == sorted(range(15))
True
>>> radix_sort([1,100,10,1000]) == sorted([1,100,10,1000])
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True
"""
RADIX = 10 # noqa: N806
placement = 1
max_digit = max(list_of_ints)
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while placement <= max_digit:
# declare and initialize empty buckets
buckets: list[list] = [list() for _ in range(RADIX)]
# split list_of_ints between the buckets
for i in list_of_ints:
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tmp = int((i / placement) % RADIX)
buckets[tmp].append(i)
# put each buckets' contents into list_of_ints
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a = 0
for b in range(RADIX):
for i in buckets[b]:
list_of_ints[a] = i
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a += 1
# move to next
placement *= RADIX
return list_of_ints
if __name__ == "__main__":
import doctest
doctest.testmod()