python实现归并排序

# 归并排序
def merge_sort(list):
  n = len(list)
  # 先将待排序的数拆开
  if n <= 1:   # 拆分到只有一个元素为止，返回。
    return list
  mid = n // 2
  # print(list[:mid])  
  # print(list[mid:])
  left_li = merge_sort(list[:mid])    # 归并排序后产生的新有序列表
  right_li = merge_sort(list[mid:])
  # print(left_li)
  # print(right_li)
  # 合并left和right，将2个有序的子序列合并为一个新的整体
  left_pointer, right_pointer = 0, 0
  # 存放合并后的结果值
  result = []
  while (left_pointer < len(left_li) and right_pointer <len(right_li) ):
     if left_li[left_pointer] > right_li[right_pointer]:
        result.append(right_li[right_pointer])
        right_pointer += 1
     else:
        result.append(left_li[left_pointer])
        left_pointer += 1
  if left_pointer < len(left_li):
    result += left_li[left_pointer:]
  if right_pointer < len(right_li):
    result += right_li[right_pointer:]
      
  return result                         


if __name__ == '__main__':
  list = [6, 7, 0, 34, 15, 2, 17]
  result = merge_sort(list)
  print(result)

 

来源：https://blog.csdn.net/taylar1357/article/details/100807183