快速排序算法--Python
发布时间：2010/1/13 21:31:38 来源：城市学习网 编辑：海蓝
研究Python中，写一个快速排序练练手：
'''
qsort.py
Quick sort
Created on Jun 18, 2009
@author: Liao
'''
from random import Random
def quick_sort(arr):
if len(arr) > 1:
qsort(arr, 0, len(arr) - 1)
def qsort(arr, start, end):
base = arr[start]
pl = start
pr = end
while pl < pr:
while pl < pr and arr[pr] >= base:
pr -= 1
if pl == pr:
break
else:
arr[pl], arr[pr] = arr[pr], arr[pl]
while pl < pr and arr[pl] <= base:
pl += 1
if pl == pr:
break
else:
arr[pl], arr[pr] = arr[pr], arr[pl]
# now pl == pr
if pl - 1 > start:
qsort(arr, start, pl - 1)
if pr + 1 < end:
qsort(arr, pr + 1, end)
r = Random()
a = []
for i in range(20):
a.append(r.randint(0, 100))
print a
quick_sort(a)
print a
