冒泡排序大家应该都很熟悉,是一个比较交换排序,时间复杂度是O(n2),之前用过java实现过,现在用python来实现一次,还有其优化
总共用了三种实现方式
话不多说,直接上代码,比较三种的性能------------------
#! -*- coding:utf-8 -*-
#冒泡排序
import time
#野路子冒泡排序
def maopaosort1(array):
time1_start = time.time()
length = len(array)
while length>1:
for i in range(length-1):
if array[i] > array[i+1]:
array[i],array[i+2] = array[i+1],array[i]
length -= 1
#print(array)
time1_end = time.time()
print(time1_end-time1_start)
#正常冒泡排序无优化
def maopaosort2(array):
time2_start = time.time()
length = len(array)
for i in range(length)[::-1]:
for j in range(i):
if array[j]>array[j+1]:
array[j],array[j+1] = array[j+1],array[j]
#print(array)
time2_end = time.time()
print(time2_end-time2_start)
#正常冒泡排序有优化
def maopaosort3(array):
time3_start = time.time()
length = len(array)
for i in range(length)[::-1]:
flag = False
for j in range(i):
if array[j]>array[j+1]:
array[j],array[j+1] = array[j+1], array[j]
flag=True
if not flag:
break
#print(array)
time3_end = time.time()
print(time3_end-time3_start)
list = [3,2,5,6,7,8,9,10,11]+list(range(12,1000))
maopaosort1(list)
print('-----------------------------')
maopaosort2(list)
print('-----------------------------')
maopaosort3(list)
运行结果如下:
在博主程序中的例子下,第三种优化后的冒泡排序比前两种性能好的不是一个数量级