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#!/usr/bin/env python3 | |
RADIX = 10 | |
# radix sort that works for non negative integers | |
def radix_sort_nonneg(lst): | |
last_iteration = False | |
radix_power = 1 | |
while not last_iteration: | |
# split into buckets | |
buckets = [[] for _ in range(RADIX)] | |
last_iteration = True # unless we find it isn't | |
for el in lst: | |
# find the digit corresponding to radix_power | |
# example with radix_power = 1000; el = 123456 | |
# el % (radix_power*RADIX) == 123456 % 10000 == 3456 | |
# 3456 // radix_power == 3456 // 1000 == 3 | |
digit = el % (radix_power*RADIX) // radix_power | |
buckets[digit].append(el) | |
if el >= radix_power*RADIX: | |
last_iteration = False | |
# flatten | |
lst = [el for bucket in buckets for el in bucket] | |
radix_power *= RADIX | |
return lst | |
def radix_sort(lst): | |
positive_ints = radix_sort_nonneg( x for x in lst if x >= 0) | |
negative_ints = radix_sort_nonneg(-x for x in lst if x < 0) | |
return [-x for x in reversed(negative_ints)] + positive_ints | |
print(radix_sort([1, 2, 3, -3, -10, 332, 123, 124, 122, 2, 321, 3, 0])) |
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