排序时间复杂度对比

Posted 2021-01-04 monster-world

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 import random
 4 import datetime
 5 
 6 #插入式排序
 7 def insert_sort(list,result):
 8     cnt = len(list)
 9     i=0
10     for i in range(cnt):
11         right = list[i]
12         result.append(right)
13         if len(result) == 1:
14             continue
15         for j in range(len(result)-1,0,-1):
16             if right < result[j-1]:
17                 result[j] = result[j-1]
18                 result[j-1] = right
19             else:
20                 break
21     return result
22 
23 #归并排序
24 def tog_sort(lists):
25     if len(lists) <= 1:
26         return lists
27     num = int(len(lists)/2)
28     left = tog_sort(lists[:num])
29     right = tog_sort(lists[num:])
30     return sort(left,right)
31 
32 def sort(left,right):
33     l,r = 0,0
34     result = []
35     while l<len(left) and r<len(right):
36         if left[l]<right[r]:
37             result.append(left[l])
38             l += 1
39         else:
40             result.append(right[r])
41             r += 1
42     result += left[l:]
43     result += right[r:]
44     return result
45 
46 if __name__ == ‘__main__‘:
47     list = []
48     result = []
49     for i in range(20000):
50         list.append(random.randint(1, 200))
51     print(‘BEFORE:‘)
52     print(list)
53     starttime = datetime.datetime.now()
54     insert_sort(list,result)
55     print(‘插入式排序:‘)
56     print(result)
57     endtime = datetime.datetime.now()
58     print((endtime - starttime).seconds,end=‘‘)
59     print(‘秒‘,end=‘‘)
60     print((endtime - starttime).microseconds,end=‘‘)
61     print(‘毫秒‘)
62 
63     starttime = datetime.datetime.now()
64     result = tog_sort(list)
65     print(‘归并排序:‘)
66     print(result)
67     endtime = datetime.datetime.now()
68     print((endtime - starttime).seconds, end=‘‘)
69     print(‘秒‘, end=‘‘)
70     print((endtime - starttime).microseconds, end=‘‘)
71     print(‘毫秒‘)

两万个数据，两种排序的时间对比，如下图：