Hanoi Tower problem

Rules:
 Only one plate can be moved at a time
 For any movement, the state of the three towers must be that the small plate is on the top and the large plate is on the top

method:
 N = 1: directly move a plate on a to C, a – > C

n=2：
 Put the small plate from a to B, a – > B
 Put the big plate from a to C, a – > C
 Put the small plate from B to C, B – > C

n=3:
 Move the two plates on a to B through C and call recursive implementation
 Move the largest plate left on a to C, a – > C
 Move the two plates on B to C with the help of a and call recursion

n=n：
 Move the N1 plates on a to B with the help of C, and call recursion
 Move the largest and only plate on a to C, a – > C
 Move n1 plates on B to C with the help of a and call recursion
def hano(n, a, b, c):
'''
Recursive implementation of Hanoi Tower
n: How many towers does it represent
a: Represents the first tower, the beginning tower
b: Represents the second tower, the middle transition tower
c: Represents the third tower, the target tower
'''
if n == 1:
print(a, ">", c)
return None
'''
if n== 2:
print(a, ">", b)
print(a, ">", c)
print(b, ">", c)
return None
'''
#Move n1 towers from tower a to Tower B with the help of tower C
hano(n1, a, c, b)
print(a, ">", c)
#Move n1 tower from Tower B to tower C with the help of tower a
hano(n1, b, a, c)
a = 'A'
b = 'B'
c = 'C'
n = 1
hano(n, a, b, c)
A > C
n = 2
hano(n, a, b, c)
A > B
A > C
B > C
n = 3
hano(n, a, b, c)
A > C
A > B
C > B
A > C
B > A
B > C
A > C
n = 5
hano(n, a, b, c)
A > C
A > B
C > B
A > C
B > A
B > C
A > C
A > B
C > B
C > A
B > A
C > B
A > C
A > B
C > B
A > C
B > A
B > C
A > C
B > A
C > B
C > A
B > A
B > C
A > C
A > B
C > B
A > C
B > A
B > C
A > C
List
 Del: delete command
#Del delete
a = [1,2,3,4,5,6]
del a[2]
print(a)
[1, 2, 4, 5, 6]
#Del delete
#If the value of ID after del is different from that before deletion, it indicates that deletion generates a new list
a = [1,2,3,4,5,6]
print(id(a))
del a[2]
print(id(a))
print(a)
1787345100360
1787345100360
[1, 2, 4, 5, 6]
#Del cannot continue to use this variable after a variable
del a
print(a)

NameError Traceback (most recent call last)
<ipythoninput15a09b634934b2> in <module>
1 # del a variable can no longer be used
> 2 del a
3 print(a)
NameError: name 'a' is not defined
List addition
#Use the plus sign to connect two lists
a = [1,2,3,4,5]
b = [5,6,7,8,9]
d = ['a', 'b', 'c']
c = a + b + d
print(c)
[1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 'a', 'b', 'c']
#Using the multiplier action list
#The list is directly multiplied by an integer
#It's equivalent to joining n lists together
a = [1,2,3,4,5]
b = a * 3
print(b)
[1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
#Membership operation
#Is to determine whether an element is in the list
a = [1,2,3,4,5,6]
b = 8
#The value of C is a Boolean value
c = b in a
print(c)
b = 4
print(b in a)
False
True
# not in
a = [1,2,3,4,5]
b = 9
print(b not in a)
True
Traversal of list
 for
 while
# for in list
a = [1,2,3,4,5]
#Print the elements in a one by one
for i in a:
print(i)
1
2
3
4
5
#The Python code written by Java and C + + programmers is like this
for i in range(0,len(a)):
print(a[i])
i += 1
1
2
3
4
5
b = ["I love you"]
for i in b:
print(i)
I love you
# range
#The variables after in are required to be iteratable
for i in range(1,10):
print(i)
print(type(range(1,10)))
1
2
3
4
5
6
7
8
9
<class 'range'>
#While loop access list
#Generally, you don't need to traverse the list while
a = [1,2,3,4,5,6]
length = len(a)
#Indx represents the subscript of the list
indx = 0
while indx < length:
print(a[indx])
indx += 1
1
2
3
4
5
6
#Double layer list loop
#A is a nested list, or doublelayer list
a = [["one", 1], ["two", 2], ["three", 3]]
for k,v in a:
print(k, "", v)
one  1
two  2
three  3
#Double list cyclic variation
#A is a nested list, or doublelayer list
a = [["one", 1, "enis"], ["two", 2], ["three", 3,4,5,6,8]]
for k,v in a:
print(k, "", v)

ValueError Traceback (most recent call last)
<ipythoninput44db702adbc386> in <module>
4 a = [["one", 1, "enis"], ["two", 2], ["three", 3,4,5,6,8]]
5
> 6 for k,v in a:
7 print(k, "", v)
ValueError: too many values to unpack (expected 2)
#Double list cyclic variation
#A is a nested list, or doublelayer list
a = [["one", 1, "enis"], ["two", 2, "zwei"], ["three", 3, "drei"]]
#This example shows that the number of K, V and W should be consistent with the number of unpacked variables
for k,v,w in a:
print(k, "", v, "", w)
one  1  enis
two  2  zwei
three  3  drei
List content: list content
 Create lists in a simple way
#For create
a = ['a', 'b', 'c']
#Create a list B with list a
#The meaning of the following code is to put all the elements in a into the new list B one by one
b = [i for i in a]
print(b)
['a', 'b', 'c']
#Multiply all elements in a by 10 to generate a new list
a = [1, 2, 3, 4, 5]
#Create a list B with list a
#The meaning of the following code is to put all the elements in a into the new list B one by one
b = [i*10 for i in a]
print(b)
[10, 20, 30, 40, 50]
#You can also filter the contents of the original list and put them into a new list
#For example, the original list needs to generate a new list B from all the even numbers in a
A = [x for X in range (1,35)] # generates a list from 1 to 34
#Generate a new list B from all even numbers in a
b = [m for m in a if m % 2 == 0]
print(b)
[2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34]
#List generators can be nested
#There are two lists a, B
A = [i for I in range (1,4)] # generate list a
print(a)
b = [i for i in range(100,400) if i % 100 == 0]
print(b)
#List generation can be nested, which is equal to the nesting of two for loops
c = [m+n for m in a for n in b]
print(c)
#The above code is equivalent to the following code
for m in a:
for n in b:
print(m+n, end=" ")
print()
#Nested list generation can also use conditional expressions
c = [m+n for m in a for n in b if m+n < 250]
print(c)
[1, 2, 3]
[100, 200, 300]
[101, 201, 301, 102, 202, 302, 103, 203, 303]
101 201 301 102 202 302 103 203 303
[101, 201, 102, 202, 103, 203]
Common functions about lists
#Len: find the length of the list
a = [x for x in range(1,100)]
print(len(a))
#Max: find the maximum value in the list
#Min: similarly
print(max(a))
b = ["man", "film", "python"]
print(max(b))
99
99
python
#List: convert data in other formats to list
a = [1,2,3]
print(list(a))
[1, 2, 3]
s = "I love you"
print(list(s))
['I', ' ', 'l', 'o', 'v', 'e', ' ', 'y', 'o', 'u']
#Convert the content generated by range into list
print(list(range(12,19)))
[12, 13, 14, 15, 16, 17, 18]