Python实现归并排序

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/3/18 14:26
# @Author  : baoshan
# @Site    :
# @File    : mergeSort.py
# @Software: PyCharm Community Edition

def MergeSort(lists):
    if len(lists) <= 1:
        return lists
    num = int(len(lists) / 2)
    left = MergeSort(lists[:num])
    right = MergeSort(lists[num:])
    return Merge(left, right)

def Merge(left, right):
    l, r = 0, 0
    result = []
    while l < len(left) and r < len(right):
        if left[l] < right[r]:
            result.append(left[l])
            l += 1
        else:
            result.append(right[r])
            r += 1
    result += left[l:]
    result += right[r:]
    return result

print(MergeSort([1, 2, 3, 4, 5, 6, 7, 90, 21, 23, 45]))

输出结果：

/Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 /Users/baoshan/PycharmProjects/myProject/python_weixin_study/mergeSort.py
[1, 2, 3, 4, 5, 6, 7, 21, 23, 45, 90]

Process finished with exit code 0