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