python排序算法和实现

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python排序算法和实现,有需要的朋友可以参考下。

# -*- coding: utf-8 -*-
# 测试各种排序算法
# link:www.jb51.net
# date:2013/2/2

#选择排序
def select_sort(sort_array):
for i, elem in enumerate(sort_array):
for j, elem in enumerate(sort_array[i:]):
if sort_array[i] > sort_array[j + i]:
#交换
sort_array[i], sort_array[j + i] = sort_array[j + i], sort_array[i]

#冒泡排序
def bubble_sort(sort_array):
for i, elem in enumerate(sort_array):
for j, elem in enumerate(sort_array[:len(sort_array) - i - 1]):
if sort_array[j] > sort_array[j + 1]:
sort_array[j], sort_array[j + 1] = sort_array[j + 1], sort_array[j]

#插入排序
def insert_sort(sort_array):
for i, elem in enumerate(sort_array):
for j, elem in enumerate(sort_array[:i]):
if sort_array[j] > sort_array[i]:
sort_array.insert(j, sort_array[i])
del sort_array[i + 1]
#归并排序
def merge_sort_wrapper(sort_array):
merge_sort(sort_array, 0, len(sort_array) - 1)

def merge_sort(sort_array, left = 0, right = 0):
if left < right:
center = (left + right) / 2
merge_sort(sort_array, left, center)
merge_sort(sort_array, center + 1, right)
merge(sort_array, left, right, center)

def merge(sort_array, left, right, center):
result = []
arrayA = sort_array[left:center + 1]
arrayB = sort_array[center + 1:right + 1]
while((len(arrayA) > 0) and (len(arrayB) > 0)):
if(arrayA[0] > arrayB[0]):
result.append(arrayB.pop(0))
else:
result.append(arrayA.pop(0))

if(len(arrayA) > 0):
result.extend(arrayA)
if(len(arrayB) > 0):
result.extend(arrayB)
sort_array[left:right + 1] = result

#快排
def quick_sort(sort_array):
if(len(sort_array) < 2):
return

left = [x for x in sort_array[1:] if x < sort_array[0]]
right = [x for x in sort_array[1:] if x >= sort_array[0]]
quick_sort(left)
quick_sort(right)
sort_array[:] = left + [sort_array[0]] + right

#shell排序
def shell_sort(sort_array):
dist=len(sort_array)/2
while dist > 0:
for i in range(dist,len(sort_array)):
tmp=sort_array[i]
j = i
while j >= dist and tmp < sort_array[j - dist]:
sort_array[j] = sort_array[j - dist]
j -= dist
sort_array[j] = tmp
dist /= 2

#基数排序,均为整数,不支持负数和重复
def radix_sort(sort_array):
max_elem = max(sort_array)
bucket_list = []
for i in range(max_elem):
bucket_list.insert(i, 0)

for x in sort_array:
bucket_list[x - 1] = -1

sort_array[:] = [x + 1 for x in range(len(bucket_list)) if bucket_list[x] == -1]

#堆排序
def heap_sort(sort_array):
#没有写出来,再想想
pass

#测试例子
def algo_sort_test(sort_array, sort_method):
sort_method(sort_array)

if __name__ == '__main__':

sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23]
algo_sort_test(sort_array, select_sort)
print sort_array

sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23]
algo_sort_test(sort_array, bubble_sort)
print sort_array

sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23]
algo_sort_test(sort_array, insert_sort)
print sort_array

sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23]
algo_sort_test(sort_array, merge_sort_wrapper)
print sort_array

sort_array = [1, 2, 3, 5, -4, 4, 10, 300, 19, 13, 16, 18, 500, 190, 456, 23]
algo_sort_test(sort_array, quick_sort)
print sort_array

sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23]
algo_sort_test(sort_array, shell_sort)
print sort_array

sort_array = [1, 2, 3, 5, 4, 10, 19, 13, 16, 18, 190, 456, 23]
algo_sort_test(sort_array, radix_sort)
print sort_array

print 'OK'


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