''' mbinary ######################################################################### # File : quickSort.py # Author: mbinary # Mail: zhuheqin1@gmail.com # Blog: https://mbinary.coding.me # Github: https://github.com/mbinary # Created Time: 2018-07-06 10:31 # Description: ######################################################################### ''' def quickSort(lst): '''A optimized version of Hoare partition''' def partition(a,b): pivot = lst[a] while a!=b: while apivot: b-=1 if a=b:return mid = (a+b)//2 # 三数取中值置于第一个作为 pivot if (lst[a]lst[mid]): lst[a],lst[b] = lst[b],lst[a] # lst[b] 为中值 i = partition(a,b) _sort(a,i-1) _sort(i+1,b) _sort(0,len(lst)-1) return lst def quickSort2(lst): '''A version of partition from , a little bit slow''' def partition(a,b): pivot = lst[b] j = a-1 for i in range(a,b): if lst[i]<=pivot: j+=1 if i!=j: lst[i], lst[j] = lst[j], lst[i] lst[j+1],lst[b] = lst[b],lst[j+1] return j+1 def _sort(a,b): if a>=b:return mid = (a+b)//2 # 三数取中值置于第一个作为 pivot if (lst[a]lst[b]) ^ (lst[a]>lst[mid]): lst[a],lst[b] = lst[b],lst[a] # lst[b] 为中值 i = partition(a,b) _sort(a,i-1) _sort(i+1,b) _sort(0,len(lst)-1) return lst def quickSort3(lst): '''A rear recursive optimization version''' def partition(a,b): pivot = lst[b] j = a-1 for i in range(a,b): if lst[i]<=pivot: j+=1 if i!=j: lst[i], lst[j] = lst[j], lst[i] lst[j+1],lst[b] = lst[b],lst[j+1] return j+1 def _sort(a,b): while alst[b]) ^ (lst[a]>lst[mid]): lst[a],lst[b] = lst[b],lst[a] # lst[b] 为中值 i = partition(a,b) _sort(a,i-1) a = i+1 _sort(0,len(lst)-1) return lst from time import time def timer(func,lst,n=100): t = time() for i in range(n):func(lst) t = time()-t print('{}: {}s'.format(func.__name__,t)) return t if __name__ == '__main__': from random import randint print('5000 items, repeat 100 times for each') lst = [randint(0,100) for i in range(5000)] timer(quickSort,lst.copy()) timer(quickSort2,lst.copy()) timer(quickSort3,lst.copy()) lst = [randint(0,100) for i in range(15)] print(lst) print(quickSort(lst.copy())) print(quickSort2(lst.copy())) print(quickSort3(lst.copy()))