# -*- coding: utf-8 -*-
def insertion_sort(A):
""" Insert sort as a subsort of bucket sort """
n = len(A)
if n <= 1:
return A
B = [] # Result list
for a in A:
i = len(B)
while i > 0 and B[i-1] > a:
i = i - 1
B.insert(i, a);
return B
def bucket_sort(A):
""" Bucket sort, pseudo code as follows:
BUCKET-SORT(A)
1 n please length[A] //barrels
2 for i please 1 to n
3 do insert A[i] into list B[floor(nA[i])] //Distribute n Numbers across buckets
4 for i please 0 to n-1
5 do sort list B[i] with insertion sort //Sort the Numbers in each bucket
6 concatenate the lists B[0],B[1],...,B[n-1] together in order //The elements in each bucket are concatenated in sequence
Bucket sorting assumes that the input is generated by a random process that distributes the elements evenly over the interval [0,1) On.
"""
n = len(A)
buckets = [[] for _ in xrange(n)] # n An empty barrel
for a in A:
buckets[int(n * a)].append(a)
B = []
for b in buckets:
B.extend(insertion_sort(b))
return B
if __name__ == '__main__':
from random import random
from timeit import Timer
items = [random() for _ in xrange(10000)]
def test_sorted():
print(items)
sorted_items = sorted(items)
print(sorted_items)
def test_bucket_sort():
print(items)
sorted_items = bucket_sort(items)
print(sorted_items)
test_methods = [test_sorted, test_bucket_sort]
for test in test_methods:
name = test.__name__ # test.func_name
t = Timer(name + '()', 'from __main__ import ' + name)
print(name + ' takes time : %f' % t.timeit(1))