Practice is an indispensable exercise in programming. Let’s take a look at recursive questions and function-related questions.
1. There is a pair of rabbits. From the 3rd month after birth, a pair of rabbits will be born every month, and the
little rabbit will give birth to a pair of rabbits every month after the 3rd month.
If the rabbits are not dead, ask the nth What is the logarithm of the rabbit in the month?
'''
作者：lsf
time:2021.1.19
有一对兔子，从出生后的第3个月起，每个月都生一对兔子，
小兔子长到第3个月后每个月又生一对兔子，
假如兔子不死，问第n个月第兔子对数为多少？
f(n)= f(n-1)+f(n-2) {n 代表月份}
'''
def rabit_twain(time):
if time==1 or time==2:
return 1
else:
month=rabit_twain(time-1)+rabit_twain(time-2)
return month
print(rabit_twain(4))
2. Complete a blog system (requires users to register, log in, publish blogs, delete blogs, add blogs, and query blog functions)
'''
作者：lsf
time:2021.1.19
'''
import sys
def ring_up():
users = []
while True:
print("欢迎登录我们的用户管理系统")
print("\t\t 1、用户注册")
print("\t\t 2、用户登录")
print("\t\t 3,进入博客")
print("\t\t 4、退出系统")
choice = input("请选择您的操作：")
if choice == "1":
while True:
print("欢迎进入到用户注册页面")
username = input("请输入用户名称：")
password = input("请输入用户密码：")
confirm_password = input("请再次确认密码：")
# 数据校验
# 用户名称不能为空
if username == None or len(username) == 0:
print("对不起，用户为空")
continue
# 用户名称不能重复
flag = False
for u in users:
if u.get("username") == username:
print("对不起，该用户已经存在，请重新注册")
flag = True
break
if flag:
continue
# 密码长度不能少于3位
if len(password) < 3:
print("对不起，密码长度不能少于3位")
continue
# 两次密码不一致
if password != confirm_password:
print("两次密码不一致")
continue
# 最后如何保存用户名称和密码
user = {"username": username, "password": password}
users.append(user)
print("用户注册成功，请登录")
break
elif choice == "2":
print("欢迎进入到用户登录页面")
username = input("请输入用户名称：")
password = input("请输入用户密码：")
# 判断用户名和密码是否存在于users
for user in users:
if user["username"] == username and user.get("password") == password:
print("恭喜您，{}，登录成功".format(username))
else:
print("对不起，登录失败，请重新登录~~")
elif choice == "3":
blong = []
print("登陆成功，您可以选择以下操作")
print("1,添加博客")
print("2,查询博客")
print("3,删除博客")
print("4,退出系统")
choice = int(input("请选择您的操作："))
if choice == 1:
print("欢迎进入添加博客页面")
content = input("请输添加内容：")
prople = int(input("1,发表博客，2取消发表"))
if prople == 1:
blong.append(content)
print("添加博客成功")
continue
else:
print("取消发表成功")
continue
elif choice == 2:
print(blong)
continue
elif choice ==3:
blong.clear()
print("删除成功")
continue
else:
sys.exit()
else:
sys.exit()
ring_up()
3. Assuming that the user can only go up to one step or two steps each time, please write a function to determine how many ways the user has to go to the nth step
'''
作者：lsf
time:2021.1.19
f(n)= f(n-1)+f(n-2)
'''
def stairs(step):
if step == 1 or step == 2:
return 1
else:
month =stairs(step - 1) +step(step - 2)
return month
print((4))
4. Find the number within 10000 that can be divisible by 5 or 6, but not divisible by both at the same time (function)
'''
作者：lsf
time:2021.1.19
f(x)=f(x-5)f(x-6)
'''
import sys
sys.setrecursionlimit(100000)
def num(n):
while n >= 0:
if n%5==0 or n%6==0 and n%30 != 0 :
print(n)
return num(n-1)
else:
return num(n-1)
print(num(1000))
5. Write a method to calculate the sum of all even subscript elements of the list (note the return value)
'''
作者：lsf
time:2021.1.19
'''
ls=[1,2,3,4,5,6,7,8,9,10,23,14,66]
l=[]
def even_number(lis):
for i in lis:
if i % 2 == 0:
l.append(i)
return sum(l)
print(even_number(ls))
6. Determine whether a number is prime (prime number)? How to declare a method?
'''
作者：lsf
time:2021.1.19
能不能被整除
'''
num=int(input("请输入一个整数："))
def is_prime(num):
for i in range(2,num//2+1):
if num % i == 0 :
return print("%d不是质数"%num)
else:
return print("%d是质数"%num)
is_prime(num)
7. Please use the function to complete the three sorts of selection, bubbling, and insertion
https://blog.csdn.net/weixin_47514459/article/details/112791073
8. A person enters the following chessboard, asks to start from the upper left corner, and finally comes out from the lower right corner (required to only move forward, not back),
question: How many moves are there?
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
'''
作者：lsf
time:2021.1.19
'''
def get_count(board):
# 求棋盘横向的宽度
width = len(board[0])
# 求纵向的高度
height = len(board)
if width == 0 and height == 0:
return 0
# 棋盘只有一个位置，也就是只有一种走法
if width == 1 and height == 1:
return 1
# 将横向第一行设置为0
for i in range(width):
board[0][i] = 1
for i in range(height):
board[i][0] = 1
for i in range(1, height):
for j in range(1, width):
board[i][j] = board[i][j - 1] + board[i - 1][j]
return board[height - 1][width - 1]
b = [[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0],[0,0,0,0,0]]
print(get_count(b))
