#coding:utf-8
#bubble sort (氣泡排序)，時間複雜度最壞為o(n2)，最優的為n
import time
def bubble_sort(alist):
'''氣泡排序
:param alist:
:return:
'''cur = 1
while cur != len(alist)-1 and len(alist) != 1:
for i in range(len(alist)-cur):
if alist[i] > alist[i+1]:
alist[i], alist[i+1] = alist[i+1], alist[i]
cur += 1
print(alist)
def bubble_sort2(alist):
for j in range(len(alist)-1):
for i in range(len(alist)-1-j):
if alist[i] > alist[i+1]:
alist[i],alist[i+1] = alist[i+1],alist[i]
print(alist)
if __name__ == "__main__":
alist = [1,2,9,6,35,77,7,8]
alist1 = [2]
bubble_sort2(alist1)
##select sort 選擇排序 ,時間複雜最優n^2,最壞也為n^2
def select_sort(alist):
for j in range(len(alist)-1):
min_index = j
for i in range(1+j,len(alist)):
if alist[min_index] > alist[i]:
min_index = i
alist[min_index],alist[j] = alist[j],alist[min_index]
return alist
if __name__ == "__main__":
alist = [3,4,5,8,1,0,23]
# print(select_sort(alist))
###插入排序
def insert_sort(alist):
for j in range(1,len(alist)):
i = j
while i>0:
if alist[i]>alist[i-1]:
alist[i],alist[i-1] = alist[i-1],alist[i]
i -= 1
else:
break
return alist
if __name__ == "__main__":
alist = [3,4,5,8,1,0,23]
# print(insert_sort(alist))
##希爾排序 ， 插入排序的優化
def shell_sort(alist):
n = len(alist)
gap = n//2
for i in range(gap,len(alist)):
j = i
for k in range(i,0,-gap):
if alist[k] < alist[k-gap]:
alist[k], alist[k-gap] = alist[k-gap], alist[k]
print(alist)
if __name__ == "__main__":
alist = [3,4,5,8,1,0,23]
# shell_sort(alist)
##快速排序,時間複雜度,最優的時間複雜度為o(logn)，最壞時間複雜度為o(n^2)
def quick_sort(alist,first,last):
if first < last:
start = first
end = last
base = alist[start]
while start =alist[start]):
start += 1
alist[end] = alist[start]
alist[start] = base
quick_sort(alist,first,start-1)
quick_sort(alist,start+1,last)
return alist
if __name__ == "__main__":
alist = [3,4,5,8,1,0,0,23]
# print("result:"+str(quick_sort(alist,0,len(alist)-1)))
#歸併演算法，時間複雜度nlogn,此演算法返回的是乙個新列表
def merge_sort(alist):
"""歸併演算法的基本實現
:param alist:列表
:return:排序後的列表
"""lens = len(alist)
if lens <= 1:
return alist
mid = lens//2
#left 採用歸併排序
常見排序演算法Python實現
氣泡排序 最優時間複雜度 o n 最壞時間複雜度 o n 2 穩定性 穩定 def bubble sort alist 氣泡排序 for j in range len alist 1,0,1 count 0 for i in range j if alist i alist i 1 alist i ...
常見排序演算法 python實現
穩定性是指序列中相同的數字在排序後相對位置不發生改變 常見的且穩定的排序演算法有冒泡 歸併 插入，其餘的為非穩定的排序演算法 def bubble sort alist for j in range len alist 1 0,1 for i in range j if alist i alist ...
常見排序演算法的python實現
氣泡排序和選擇排序 defbubblesort alist for i in range len alist 1 0,1 for j in range i if alist j alist j 1 alist j alist j 1 alist j 1 alist j return alist al...