排序算法 - 归并排序

Posted 2021-03-06 yangjunh

"""
归并排序
"""

def merge_sort(li):
# 递归出口
if len(li) == 1:
return li

# 第1步：先分
mid = len(li) // 2
left = li[:mid]
right = li[mid:]
left_one = merge_sort(left)
right_one = merge_sort(right)

# 第2步: 再合 - 从内到外执行
result_li = merge(left_one,right_one)
return result_li

def merge(left_one,right_one):
"""开始合并"""
result = []
while len(left_one) > 0 and len(right_one) > 0:
if left_one[0] <= right_one[0]:
result.append(left_one.pop(0))
else:
result.append(right_one.pop(0))
result += left_one
result += right_one

return result

li = [6,5,3,1,8,7,2,4]
print(merge_sort(li))