python算法实践6 堆排序
#堆排序
def Heapify(mylist, start, end):
left = 0
right = 0
maxv = 0
left = start * 2
right = start * 2 + 1
while left <= end:
maxv = left
if right <= end:
if mylist[left] < mylist[right]:
maxv = right
else:
maxv = left
if mylist[start] < mylist[maxv]:
tmp = mylist[maxv]
mylist[maxv] = mylist[start]
mylist[start] = tmp
start = maxv
else:
break
left = start * 2
right = start * 2 + 1
def BuildHeap(mylist):
size = len(mylist)
i = (size -1) // 2;
while i >= 0:
Heapify(mylist, i, size - 1)
i = i - 1
def HeapSort(mylist):
BuildHeap(mylist)
i = len(mylist) - 1
while i >= 0:
tmp = mylist[0]
mylist[0] = mylist[i]
mylist[i] = tmp
Heapify(mylist, 0, i - 1)
i = i - 1
mylist0 = [11, 23, 1, 24, 112, 200, 9, 32]
HeapSort(mylist0)
print(mylist0)
相关文档：
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� ......
python字典排序
1、
准备知识：
在python里，字典dictionary是内置的数据类型，是个无序的存储结构，每一元素是key-value对：
如：dict = {‘username’：‘password’，‘database’：‘master’}，其中‘username’和& ......
#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 ......
#直接选择排序
def SelectSort(mylist):
size = len(mylist)
i = 0
for i in range(0, size):
k = i
for j in range(i + 1, size):
if mylist[j] < mylist[k]:
k = j
if k != i:
tmp = mylist[i]
......
