python开发之路Day17-算法设计(冒泡排序选择排序插入排序二叉树)

Posted 2020-08-02 南非波波

s12-20160514-day17

pytho自动化开发 day17

Date:2016.05.14

    @南非波波

课程大纲：

http://www.cnblogs.com/alex3714/articles/5474411.html

一、冒泡排序算法

#!/usr/local/env python3
\'\'\'
Author:@南非波波
Blog:http://www.cnblogs.com/songqingbo/
E-mail:[e-mail]
\'\'\'
import random,time
#m冒泡排序

def bubble_up1(array):
    \'\'\'
    m冒泡排序算法
    :param array:
    :return: count: 6190862 time: 6.706383466720581
    \'\'\'
    count = 0
    for i in range(len(array)):
        for j in range(len(array) - 1 - i):
            if array[j] > array[j + 1]:
                temp = array[j + 1]
                array[j + 1] = array[j]
                array[j] = temp
                count += 1
    print("count:", count)
    print("array:", array)

def bubble_up2(array):
    \'\'\'
    m冒泡排序算法
    :param array:
    :return:count: 5000 time: 3.825218915939331
    \'\'\'
    count = 0
    for i in range(len(array)):
        for j in range(len(array) - 1 - i):
            big_temp = j
            if array[big_temp] > array[j + 1]:
                big_temp = j + 1
        temp = array[big_temp]
        array[i] = array[big_temp]
        array[big_temp] = temp
        count += 1
    print("count:", count)
    print("array:", array)


if __name__ == \'__main__\':
    array = []
    for i in range(5000):
        array.append(random.randrange(1000))

    time_start = time.time()
    bubble_up2(array)
    time_end = time.time()
    #
    print(array[0:100])
    print("time:",time_end - time_start)

二、 选择排序

def select1(array):
    \'\'\'
    选择排序算法v1
    :param array:
    :return:count: 1996750 time: 3.2961885929107666
    \'\'\'
    count = 0
    for i in range(len(array)):
        for j in range(i,len(array)):
            if array[i] > array[j]:
                temp = array[j]
                array[j] = array[i]
                array[i] = temp
                count += 1
    print("count:",count)
    print("array:",array)

def select2(array):
    \'\'\'
    选择排序算法v2
    :param array:
    :return:count: 5000 time: 2.4801418781280518
    \'\'\'
    count = 0
    for i in range(len(array)):
        smallest_index = i
        for j in range(i,len(array)):
            if array[smallest_index] > array[j]:
                smallest_index = j
        temp = array[smallest_index]
        array[smallest_index] = array[i]
        array[i] = temp
        count += 1
    print("count:",count)
    print("array:",array)

三、直接插入排序算法

def insert1(array):
    \'\'\'
    插入排序算法
    :param array:
    :return: count: 4999 time: 3.685210704803467
    \'\'\'
    count = 0
    for index in range(1, len(array)):
        current_val = array[index]  # 先记下来每次大循环走到的第几个元素的值
        position = index

        while position > 0 and array[
                    position - 1] > current_val:  # 当前元素的左边的紧靠的元素比它大,要把左边的元素一个一个的往右移一位,给当前这个值插入到左边挪一个位置出来
            array[position] = array[position - 1]  # 把左边的一个元素往右移一位
            position -= 1  # 只一次左移只能把当前元素一个位置 ,还得继续左移只到此元素放到排序好的列表的适当位置 为止

        array[position] = current_val  # 已经找到了左边排序好的列表里不小于current_val的元素的位置,把current_val放在这里
        count += 1
    print("count:", count)
    print(array)

四、快速排序

def quick_sort(array,start,end):
    \'\'\'
    快速排序算法
    :param array:
    :param start:
    :param end:
    :return:time: 0.03600192070007324
    \'\'\'
    if start >= end:
        return
    k = array[start]
    left_flag = start
    right_flag = end
    while left_flag < right_flag:
        while array[right_flag] > k:
            right_flag -= 1
        temp = array[right_flag]
        array[left_flag] = array[right_flag]
        array[right_flag] = temp

        while array[left_flag] <= k:
            left_flag += 1
        temp = array[left_flag]
        array[left_flag] = array[right_flag]
        array[right_flag] = temp

    quick_sort(array,start,left_flag - 1)
    quick_sort(array,left_flag + 1,end)