2019.9.24- merge sort (code)

# coding:utf-8

def merge_sort(alist):
"""歸幷排序"""
n = len(alist)
if n <= 1:
return alist
mid = n//2

# Left using an ordered list of the new formed Bing normalized sorted
left_li = merge_sort (alist [: MID])

# new list ordered formed after normalization using the right sort Bing
right_li = merge_sort (alist [mid: ])

# The two ordered into a new sequence of whole
# Merge (left, right)
left_pointer, right_pointer = 0, 0
Result = []

while left_pointer < len(left_li) and right_pointer < len(right_li):
if left_li[left_pointer] < right_li[right_pointer]:
result.append(left_li[left_pointer])
left_pointer += 1
else:
result.append(right_li[right_pointer])
right_pointer += 1

result += left_li[left_pointer:]
result += right_li[right_pointer:]
return result


if __name__ == "__main__":
li = [54, 26, 93, 17, 77, 31, 44, 55, 20]
print(li)
sorted_li = merge_sort(li)
print(li)
print(sorted_li)

 

 

 

 

 

 

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Origin www.cnblogs.com/lishuide/p/11581249.html