Python实现桶排序与快速排序算法结合应用示例
本文实例讲述了Python实现桶排序与快速排序算法结合应用的方法。分享给大家供大家参考，具体如下：
#-*- coding: UTF-8 -*-
import numpy as np
from QuickSort import QuickSort
def BucketSort(a, n):
barrel = {}
for i in xrange(0,n):
barrel.setdefault(i, [])
min = np.min(a)
max = np.max(a)
for x in a:
for i in xrange(0,n-1):
if x >= min +i* (max - min)/n and x < min +(i +1) * (max - min)/n:
barrel[i].append(x)
elif i == n-2 and x >= min +(i +1) * (max - min)/n:
barrel[i+1].append(x)
k = 0
for i in xrange(0,n):
if len(barrel[i]) != 0:
arr = np.array(barrel[i])
QuickSort(arr, 0, len(barrel[i]) -1)
for x in arr:
a[k] = x
k += 1
if __name__ == '__main__':
a = np.random.randint(0, 100, size = 10)
print "Before sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"
BucketSort(a, 10)
print "After sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"
快速排序QuickSort：
#-*- coding: UTF-8 -*-
import numpy as np
def Partition(a, i, j):
x = a[i] #将数组的第一个元素作为初始基准位置
p = i #同时记录下该元素的位置
while i < j:
while i < j and a[j] >= x:
j -= 1
while i < j and a[i] <= x:
i += 1
if i != j:
a[i], a[j] = a[j], a[i] #交换a[i]与a[j]
a[p], a[i] = a[i], a[p] #将a[p]与a[i]进行交换
p = i #得到分隔位置
return p
def QuickSort(a, i, j):
if i < j:
p = Partition(a, i, j)
QuickSort(a, i, p-1)
QuickSort (a, p+1, j)
if __name__ == '__main__':
a = np.random.randint(0, 100, size = 100)
print "Before sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"
QuickSort(a, 0, a.size - 1)
print "After sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"
程序运行结果：
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希望本文所述对大家Python程序设计有所帮助。
