二叉树(前、中、后序遍历)
class BinaryTree(object):
def __init__(self,data):
self.__left = None
self.__right = None
self.__data = data
def __del__(self):
del self.__data
def add_left_node(self,data):
if self.__left:
print("Left node exist!")
else:
self.__left = BinaryTree(data)
return self.__left
def add_right_node(self,data):
if self.__right:
print("Right node exist!")
else:
self.__right = BinaryTree(data)
return self.__right
def show(self):
print(self.__data)
def pre_order(self):#前序遍历
print(self.__data,end=" ")
if self.__left:
self.__left.pre_order()
if self.__right:
self.__right.pre_order()
def in_order(self):#中序遍历
if self.__left:
self.__left.in_order()
print(self.__data,end=" ")
if self.__right:
self.__right.in_order()
def post_order(self):#后序遍历
if self.__left:
self.__left.post_order()
if self.__right:
self.__right.post_order()
print(self.__data,end=" ")
if __name__ == "__main__":
root = BinaryTree("root")
a = root.add_left_node("A")
b = root.add_right_node("B")
c = a.add_right_node("C")
d = b.add_left_node("D")
e = b.add_right_node("E")
root.show()
root.pre_order()
print("")
root.in_order()
print("")
root.post_order()运行结果：
root
root A C B D E
A C root D B E
C A D E B root小根堆
heapq 模块提供了堆算法。heapq是一种子节点和父节点排序的树形数据结构。这个模块提供heap[k] <= heap[2*k+1]并且heap[k] <= heap[2*k+2]，根的下标从0开始。
import heapq
import random
data = random.sample(range(101),10)#生成10个100以内的随机测试数据
print(data)
heapq.heapify(data)#堆化测试数据
print(data)
heapq.heappush(data,28)#新元素入堆，并重新堆化所有数据
print(data)
heapq.heappop(data)#删除最小数据，并重新堆化所有数据
print(data)
heapq.heappushpop(data,100)#删除最小元素，新元素入堆，并重新堆化所有数据
print(data)
heapq.heapreplace(data,50)#功能和heapq.heappushpop一样
print(data)
maxs = heapq.nlargest(3,data)
print(maxs)
mins = heapq.nsmallest(3,data)
#mins = heapq.nsmallest(3,data,key=str)按指定规则返回最小的3个元素
print(mins)
运行结果：
[80, 55, 34, 75, 15, 83, 56, 38, 70, 35]
[15, 35, 34, 38, 55, 83, 56, 75, 70, 80]
[15, 28, 34, 38, 35, 83, 56, 75, 70, 80, 55]
[28, 35, 34, 38, 55, 83, 56, 75, 70, 80]
[34, 35, 56, 38, 55, 83, 100, 75, 70, 80]
[35, 38, 56, 50, 55, 83, 100, 75, 70, 80]
[100, 83, 80]
[35, 38, 50]凯撒移位
import string
low_case = string.ascii_lowercase
up_case = string.ascii_uppercase
before = low_case + up_case #abcdefghijklmnoqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
print("======== 欢迎使用凯撒移位 ========")
print(" Author:Mochazz")
test_string = input('请输入你要解密的密文：')
for i in range(1,26):
after = low_case[i:] + low_case[:i] + up_case[i:] + up_case[:i]
# print(after)
table = ''.maketrans(before,after)
print('移%d位：'%i + test_string.translate(table))运行结果：
======== 欢迎使用凯撒移位 ========
Author:Mochazz
请输入你要解密的密文：Uif rvjdl cspxo gpy kvnqt pwfs uif mbaz eph
移1位：Vjg swkem dtqyp hqz lworu qxgt vjg ncba fqi
移2位：Wkh txlfn eurzq ira mxpsv ryhu wkh odcb grj
移3位：Xli uymgo fvsar jsb nyqtw sziv xli pedc hsk
移4位：Ymj vznhp gwtbs ktc ozrux tajw ymj qfed itl
移5位：Znk waoiq hxuct lud pasvy ubkx znk rgfe jum
移6位：Aol xbpjr iyvdu mve qbtwz vcly aol shgf kvn
移7位：Bpm ycqks jzwev nwf rcuxa wdmz bpm tihg lwo
移8位：Cqn zdrlt kaxfw oxg sdvyb xena cqn ujih mxp
移9位：Dro aesmu lbygx pyh tewzc yfob dro vkji nyq
移10位：Esp bftnv mczhy qzi ufxad zgpc esp wlkj ozr
移11位：Ftq cguow ndaiz raj vgybe ahqd ftq xmlk pas
移12位：Gur dhvpx oebja sbk whzcf bire gur ynml qbt
移13位：Hvs eiwqy pfckb tcl xiadg cjsf hvs zonm rcu
移14位：Iwt fjxrz qgdlc udm yjbeh dktg iwt apon sdv
移15位：Jxu gkysa rhemd ven zkcfi eluh jxu bqpo tew
移16位：Kyv hlztb sifne wfo aldgj fmvi kyv crqp ufx
移17位：Lzw imauc tjgof xgp bmehk gnwj lzw dsrq vgy
移18位：Max jnbvd ukhpg yhq cnfil hoxk max etsr whz
移19位：Nby kocwe vliqh zir dogjm ipyl nby futs xia
移20位：Ocz lpdxf wmjri ajs ephkn jqzm ocz gvut yjb
移21位：Pda mqeyg xnksj bkt fqilo kran pda hwvu zkc
移22位：Qeb nrfzh yoltk clu grjmp lsbo qeb ixwv ald
移23位：Rfc osgai zpmul dmv hsknq mtcp rfc jyxw bme
移24位：Sgd pthbj aqnvm enw itlor nudq sgd kzyx cnf
移25位：The quick brown fox jumps over the lazy dog类型转换
类型转换可以使用str()、list()、dict()等内置方法，当需要对大量数据进行类型转换时，内置函数map()可以提供非常高的效率。
import timeit
t1 = timeit.timeit('"=".join([str(n) for n in range(100)])',number=10000)
print('耗时：',t1)
t2 = timeit.timeit('"=".join(str(n) for n in range(100))',number=10000)
print('耗时：',t2)
t3 = timeit.timeit('"=".join(map(str,range(100)))',number=10000)
print('耗时：',t3)运行结果：
耗时： 0.31382967308271886
耗时： 0.34856061037248814
耗时： 0.24415366054608445字符串加解密
from itertools import cycle
def crypt(source,key):
result = ''
temp = cycle(key)#将key首尾相连形成一个圆环，使用next会一直循环
for ch in source:
result += chr(ord(ch)^ord(next(temp)))
return result
source = input('请输入你要加密的明文：')
key = input('秘钥为：')
encrypted = crypt(source,key)
print('加密后的密文为：%s' % encrypted)
print('解密后的密文为：%s' % crypt(encrypted,key))运行结果：
请输入你要加密的明文：Mochazz
秘钥为：hack
加密后的密文为：%
解密后的密文为：Mochazz加解密原理：
其实就是用了^(异或)运算
加密：string^key=明文^秘钥=密文
解密：string^key^key=密文^秘钥=string^0=string=明文
pycrypto
Python3.5不支持pycrypto，使用以下命令可以安装pycrypto
pip install --use-wheel --no-index --find-links=https://github.com/sfbahr/PyCrypto-Wheels/raw/master/pycrypto-2.6.1-cp35-none-win_amd64.whl pycrypto使用rsa模块实现消息加解密
import rsa
key = rsa.newkeys(3000)
public_key = key[0]
private_key = key[1]
msg = "Mochazz"
print("Before:%s" % msg)
msg = msg.encode()
crypto_msg = rsa.encrypt(msg,public_key)
print("Crypto:%s" % crypto_msg)
decrypto_msg = rsa.decrypt(crypto_msg,private_key)
print("Decrypto:%s" % decrypto_msg.decode())运行结果：
Before:Mochazz
Crypto:b'.\x1b\x05\xf6\x9a\xf4\x93\x0b-P+\xda\xcd\xa0\x05\xa11rxEl0F\xceZ\xa9\x814\xb8\x93\xcfu@?\xca\x06\xae\xcc3\xe3H\xde+\x84\xe8s\xbdL"&\x86\xf4\x165\x89\x8d\xd4\xcf\xd9\x89j\xf4\x91lX\x9f\xe4\xf29c\x97\xee\xc5w\x87\x06\xc0\x1b\x99\xa1\x9e\xf1\xdf\xb0\xd41?\x94|\x9a\xf9\x9f\xc7\xa5uz\x8e\xa8\x07\xfc\x89\xd5\t\\y\x0e\x91\x7f\xf7\x9cZ\xade\xf5.\x05\x8e)|\x1fp\x9f)[m\xd0\x18\xd6g,\x1a\x82Mc\x82\x1b|+\x97\x1c\x9e\x91\x01\x08\xf8V\xd2?\xf0(\xf8pf;\x05$Y\x14\x1d\x85h\x85\xde\xcd\xf2\xdetU\xb1(\xf2\x03x\x82\xcf\xc9$\x85\xd3\x08|=cF\x82z\x8f\x04%\x8a\x0f\xa0\xebB"=\xeb\xcf\xee\x1b\xa4\xefr+\xc8\xaau\xed~\xd7P\xe9\xbez]\xd5\xe1\x1cjBs;z`\xfbrZ6Xc\xb5\x80\xe9\x95\xd0tL\x84p\xf7\xf6,\xcd\xd9\xbb^g\xa0\x83\xeb\xad]\x8e\x9d\xf3\xc6F\xc9\xa07\r $\x89=\x19x^\'\x82\x18\xdf\xc9\'\x9aq\xba^\xab\xc4\xea\x06\x04)\xf7\x99A\x8e\x11\xcf\xd3\xb1\x9c\xffS\xa5I[n\xa1\xfa+\xedw\x1fF\xec\xe9\x0c\xff\x03D\x17\x9b:G\xea\x92W\xdd\xc7\xce\x8f\x85\x8c\x9c\xef\xb7\xf5H\xe9\x17\r-\xde\x1f\x00\xd9r\x9b\xaa\x11\xfb\xfa\x14i$\x02\xf0\x15?\xa0q\x98\xb6\x12\xd6\xe2s[S \x06S\x19\x92\xb4\x94L~3\xb9)\xf8\x9b'
Decrypto:Mochazz