python代码实现经典排序算法

时间：2023-03-08 19:53:09

　　排序算法在程序中有至关重要的作用, 不同算法的时间复杂度和空间复杂度都有所区别, 这影响着程序运行的效率和资源占用的情况, 经常对一些算法多加练习, 强化吸收, 可以提高对算法的理解, 进而运用到实践中, 以下是常用的一些算法排序思维, 将以最简单的代码块呈现 :

冒泡排序

 numbers = [58,35,78,12,6,19,-15,167]

 #从小到大

 for i in range(len(numbers)-1):#需要比较几轮

      for j in range(len(numbers)-1-i):  #内部数据比几次

         if  numbers[j]  >  numbers[j+1]:

              #交换位置

              numbers[j],numbers[j+1] = numbers[j+1],numbers[j]

  print(numbers)

选择排序

 numbers = [58,35,78,12,6,19,-15,167]

 for i in range(len(numbers)-1):   #要取多少次

     index = i

     for j in range(i+1,len(numbers)):

         if numbers[j] < numbers[index]:

             index = j

     numbers[i],numbers[index]= numbers[index],numbers[i]

  print(numbers)

插入排序

 numbers = [58,35,78,12,6,19,-15,167]

 for i in range(1,len(numbers)):

     j = i - 1

     if numbers[i] <  numbers[j]:

         temp = numbers[i]

         numbers[i] = numbers[j]

         j = j -1

         while j >= 0 and temp < numbers[j]:

             numbers[j+1] = numbers[j]

             j = j -1

         numbers[j+1] = temp

 print(numbers)

希尔排序

 numbers = [58,35,78,12,6,19,-15,167]

 numLen = len(numbers)

 while numLen > 1:

     numLen = numLen // 2

     for i in range(numLen, len(numbers)):

         for j in range(i % numLen, i, numLen):

             if numbers[i] < numbers[j]:

                 numbers[i], numbers[j] = numbers[j], numbers[i]

 print(numbers)

快速排序

 numbers = [58,35,78,12,6,19,-15,167]

 def sorting(begin, end):

     if begin > end:

         return

     b, e = begin, end

     pivot = numbers[b]

     while b < e:

         while b < e and numbers[e] > pivot:

             e -= 1

         while b < e and numbers[b] <= pivot:

             b += 1

         numbers[b], numbers[e] = numbers[e], numbers[b]

     numbers[b], numbers[begin] = pivot, numbers[b]

     sorting(begin, b - 1)

     sorting(e + 1, end)

 sorting(0, len(numbers) - 1)

 print(numbers)

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