python16_day39【算法】

复习：

　　1.递归

• 调用自身
• 结束条件

一、冒泡算法

 def bubble_sort(numbs):
     for i in range(len(numbs)-1):       # 这个循环负责设置冒泡排序进行的次数。
         for j in range(len(numbs)-i-1): # j为列表索引， -1为了报错IndexError: list index out of range
             if numbs[j] > numbs[j+1]:
                 numbs[j], numbs[j+1] = numbs[j+1], numbs[j]
     return numbs
 nums = [5,2,45,6,8,2,1]

 print(bubble_sort(nums))

bubble_sort

二、冒泡优化版

 def bubble_sort(numbs):
     for i in range(len(numbs)-):       # 这个循环负责设置冒泡排序进行的次数。
         exchange = False
         for j in range(len(numbs)-i-): # j为列表索引， -1为了报错IndexError: list index out of range
             if numbs[j] > numbs[j+]:
                 numbs[j], numbs[j+] = numbs[j+], numbs[j]
                 exchange = True
         if not exchange:
             break
     return numbs
 nums = [,,,,,,]

 print(bubble_sort(nums))

 bubble_sort

三、快排

 import random
 import time

 def quick_sort_(data, left, right):
     if left < right:
         mid = partition(data, left, right)
         quick_sort_(data, left, mid - 1)
         quick_sort_(data, mid + 1, right)

 def partition(data, left, right):
     tmp = data[left]        # 拿到最左边的数
     while left < right:     # 左右不碰的时候一直走。
         while left < right and data[right] >= tmp:  # 从右边找
             right -= 1  # 如果右边的大，右边向左移
         data[left] = data[right]  # 如果右边的小，移到左边去。
         while left < right and data[left] <= tmp:   # 从左边找
             left += 1
         data[right] = data[left]
     data[left] = tmp  # 左右碰上了，就把TMP放回来
     return left     # 返回mid

 def quick_sort(data):
     return quick_sort_(data, 0, len(data)-1)

 data = list(range(10000))
 random.shuffle(data)
 quick_sort(data)

quick_sort