Question

我在python中进行了合并排序，只是为了更好地了解它的工作方式。该代码可以正常工作，但是我想知道是否有人可以批评我所写的内容。可以提高效率吗？
我预计我的递归还有一些改进的余地-该函数在调用并运行后会继续运行。我通过简单地在递归调用后立即给它返回来防止它不必要地继续，但是我不确定是否有更好的方法。

此外，我还必须在输出中指定要返回值的索引0，因为函数的合并部分会生成多维数组。

"""
2019-10-17

This project simply re-creates common sorting algorithms
for the purpose of becoming more intimately familiar with 
them.
"""

import random
import math

#Generate random array
array = [random.randint(0, 100) for i in range(random.randint(5, 100))]
print(array)

#Merge Sort
def merge(array, split = True):
    split_array = []
    #When the function is recursively called by the merging section, the split will be skipped
    continue_splitting = False
    if split == True:
        #Split the array in half
        for each in array:
            if len(each) > 1:
                split_array.append(each[:len(each)//2])
                split_array.append(each[len(each)//2:])
                continue_splitting = True
            else:
                split_array.append(each)
    if continue_splitting == True:
        sorted_array = merge(split_array)
        #A return is set here to prevent the recursion from proceeding once the array is properly sorted
        return sorted_array
    else:
        sorted_array = []
        if len(array) != 1:
            #Merge the array
            for i in range(0, len(array), 2):
                #Pointers are used to check each element of the two mergin arrays
                pointer_a = 0
                pointer_b = 0
                #The temp array is used to prevent the sorted array from being corrupted by the sorting loop
                temp = []
                if i < len(array) - 1:
                    #Loop to merge the array
                    while pointer_a < len(array[i]) or pointer_b < len(array[i+1]):
                        if pointer_a < len(array[i]) and pointer_b < len(array[i+1]):
                            if array[i][pointer_a] <= array[i + 1][pointer_b]:
                                temp.append(array[i][pointer_a])
                                pointer_a += 1
                            elif array[i + 1][pointer_b] < array[i][pointer_a]:
                                temp.append(array[i + 1][pointer_b])
                                pointer_b += 1
                        #If the pointer is equal to the length of the sub array, the other sub array will just be added fully
                        elif pointer_a < len(array[i]):
                            for x in range(pointer_a, len(array[i])):
                                temp.append(array[i][x])
                                pointer_a += 1
                        elif pointer_b < len(array[i + 1]):
                            for x in range(pointer_b, len(array[i + 1])):
                                temp.append(array[i + 1][x])
                                pointer_b += 1
                else:
                    for each in array[i]:
                        temp.append(each)
                sorted_array.append(temp)
            if len(sorted_array) != 1:
                #Recursively sort the sub arrays
                sorted_array = merge(sorted_array, False)
    return sorted_array


sorted_array = merge([array])[0]
print()
print(sorted_array)

这种合并排序可以更有效吗？

0 个答案: