python算法实践7 归并排序
def MergeSort(mylist, low, mid, high):
i = low
j = mid + 1
tmp = []
while i <= mid and j <= high:
if mylist[i] <= mylist[j]:
tmp.append(mylist[i])
i = i + 1
else:
tmp.append(mylist[j])
j = j + 1
while i <= mid:
tmp.append(mylist[i])
i = i + 1
while j <= high:
tmp.append(mylist[j])
j = j + 1
for k in range(low, high):
mylist[k] = tmp[k]
mylist0 = [1, 3, 5, 7, 9, 11, 6, 8, 66, 88, 100]
MergeSort(mylist0, 0, 5, len(mylist0) - 1)
print(mylist0)
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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]
......
#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
......
