简单选择排序

最新推荐文章于 2021-04-02 17:33:42 发布

tanweii163

最新推荐文章于 2021-04-02 17:33:42 发布

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分类专栏：算法文章标签：选择排序 python

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算法说明

简单选择排序是一种选择排序。

选择排序：每趟从待排序的记录中选出关键字最小的记录，顺序放在已排序的记录序列末尾，直到全部排序结束为止。

python示例代码

#!/usr/bin/env python
import random

array = []

# generat random list
for n in range(10):
    array.append(random.randint(1, 20))

print('before sort:', array)

for x in range(0, len(array)-1):

    minIndex = x

    # found minIndex
    for y in range(x+1, len(array)):
        if array[y] < array[minIndex]:
            minIndex = y

    # sway x and minIndex
    if x != minIndex:
        tmp = array[x]
        array[x] = array[minIndex]
        array[minIndex] = tmp

    print('sorting...round', x+1, ':', array)

print('after sort:', array)

运行结果示例

before sort: [19, 17, 18, 5, 12, 7, 11, 18, 13, 18]
sorting...round 1 : [5, 17, 18, 19, 12, 7, 11, 18, 13, 18]
sorting...round 2 : [5, 7, 18, 19, 12, 17, 11, 18, 13, 18]
sorting...round 3 : [5, 7, 11, 19, 12, 17, 18, 18, 13, 18]
sorting...round 4 : [5, 7, 11, 12, 19, 17, 18, 18, 13, 18]
sorting...round 5 : [5, 7, 11, 12, 13, 17, 18, 18, 19, 18]
sorting...round 6 : [5, 7, 11, 12, 13, 17, 18, 18, 19, 18]
sorting...round 7 : [5, 7, 11, 12, 13, 17, 18, 18, 19, 18]
sorting...round 8 : [5, 7, 11, 12, 13, 17, 18, 18, 19, 18]
sorting...round 9 : [5, 7, 11, 12, 13, 17, 18, 18, 18, 19]
after sort: [5, 7, 11, 12, 13, 17, 18, 18, 18, 19]

算法时间复杂度

简单排序的时间复杂度为O(N2) (N平方，这个markdown编辑器打不出来)