python算法实践4 快速排序
#快速排序
def Partition(mylist, low, high):
tmp = mylist[low]
while low < high:
while low < high and mylist[high] >= tmp:
high = high - 1
if low < high:
mylist[low] = mylist[high]
low = low + 1
while low < high and mylist[low] <= tmp:
low = low + 1
if low < high:
mylist[high] = mylist[low]
high = high - 1
mylist[low] = tmp
return low
def QuickSort(mylist, low, high):
if low < high:
pivotpos = Partition(mylist, low, high)
QuickSort(mylist, low, pivotpos - 1)
QuickSort(mylist, pivotpos + 1, high)
mylist0 = [11, 10, 3, 12, 33, 1000, 1, 333, -11]
QuickSort(mylist0, 0, len(mylist0) - 1)
print(mylist0)
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def test2():
32 db = util.DBUnit('mysql_ab') &nb ......
逐步演进
f=open('/etc/motd','r')
longest=0
while True:
lineLen=len(f.readline().strip())
if not lineLen: break
if lineLen > longest:
longest=lineLen
f.close()
return longest
问题：一直占� ......
多个执行线程经常要共享数据，如果仅仅读取共享数据还好，但是如果多个线程要修改共享数据的话就可能出现无法预料的结果。
假如两个线程对象t1
和t2
都要对数值num=0
进行增1运算，那么t1
和t2
都各对num
修改10
次的话，那么num
最终的结果应该为20
。但是如果当t1
取得num
的值时（假如此 ......
# 直接插入排序
def InsertSort(mylist):
size = len(mylist)
i = 1
for i in range(1, size):
if mylist[i] < mylist[i - 1]:
tmp = mylist[i]
j = i - 1
mylist[j + 1] = mylist[j]
j = j - 1
while j > ......
#冒泡排序
def BubbleSort(mylist):
n = len(mylist)
i = 0
j = 0
bExchange = False
for i in range(1, n):
bExchange = False
j = n - 1
while j >= i:
if mylist[j] < mylist[j - 1]:
tmp = mylist[j]
myli ......
