冒泡排序
"""
### 时间复杂度：即程序运行的大概次数
#该时间复杂度 O(n^2)
def bubble_sort(li):
for i in range(len(li)-1): # 趟的次数，最后一趟就不用走了
flag = True
for j in range(len(li)-1-i): # 最后一个数不用比较，以及已经走了多少趟
if li[j] > li[j+1]:
li[j], li[j+1] = li[j+1], li[j]
flag = False
if flag:
return
li = [7, 5, 4, 6, 3, 8, 2, 9, 1]
bubble_sort(li)
print(li)
"""
选择排序
"""
### 选择排序
# 时间复杂度：O(n^2)
def select_sort(li):
for i in range(len(li)):
minloc = i # 假设默认第一个是最小的
for j in range(i+1, len(li)):
if li[minloc] > li[j]:
li[minloc], li[j] = li[j], li[minloc]
li = [7, 5, 4, 6, 3, 8, 2, 9, 1]
select_sort(li)
print(li)
"""
插入排序
"""
### 插入排序
# 时间复杂度：O(n^2)
def insert_sort(li):
for i in range(1, len(li)):
temp = li[i] # i = 2 temp=li[2]=4
j = i - 1 # j = 1
while j >= 0 and li[j] > temp:
li[j+1] = li[j] #[[5,7,7,6,3,8,2,9,1]] ==> [5,5,7,6,3,8,2,9,1]
j = j - 1 # j = 0
li[j+1] = temp
li = [7, 5, 4, 6, 3, 8, 2, 9, 1]
insert_sort(li)
print(li)
"""
快排
"""
#### 快排
# 时间复杂度是：O(nlogn)
def partition(li, left, right): # O(n)
temp = li[left]
while left < right:
while left < right and li[right] >= temp:
right = right - 1
li[left] = li[right] # 将大于小于归为中间数扔到前面去
while left < right and li[left] <= temp:
left = left + 1
li[right] = li[left]
li[left] = temp
return left # 把中间位置的返回出去
def quick_sort(li, left, right):
if left < right:
mid = partition(li, left, right) # 归为函数
quick_sort(li, left, mid-1) # O(logn)
quick_sort(li, mid+1, right)
li = [7, 5, 4, 6, 3, 8, 2, 9, 1]
quick_sort(li, 0, len(li)-1)
print(li)
"""