more code:

https://github.com/arthur1573/DataStructures-Algorithms-Python

// O(n)

def print_items(n):
    for i in range(n):
        print(i)

print_items(10)

// drop constants

// O(n) + O(n) != O(2n) == O(n)

def print_items(n):
    for i in range(n):
        print(i)
    for j in range(n):
        print(j)

print_items(10)

// O(n^2)

def print_items(n):
    for i in range(n):
        for j in range(n):
            print(i,j)
    
print_items(10)

// O(n^2)

// O(n) * O(n) * O(n) != O(n^3) == O(n^2)

def print_items(n):
    for i in range(n):
        for j in range(n):
            for k in range(n):   
                print(i,j,k)

print_items(10)

// O(n^2) + O(n) = O(n^2 + n) = O(n^2)

def print_items(n):
    for i in range(n):
        for j in range(n):
            print(i,j)

    for k in range(n):
        print(k)

print_items(10)

// O(1)

def add_items(n):
    return n

// O(1)

def add_items(n):
    return n + n

// O(1)

def add_items(n):
    return n + n + n

// O(log n)

// log2_8 = 3

// O(a) + O(b) = O(a + b)

def print_items(a,b):
    for i in range(a):
        print(i)

    for j in range(b):
        print(j)

// O(a * b)

def print_items(a,b):
    for i in range(a):
        for j in range(b):
            print(i,j)

class Cookie:
    def __init__(self, color):
        self.color = color

cookie_one = Cookie('green')
cookie_two = Cookie('blue')

class Cookie:
    def __init__(self, color):
        self.color = color
    def get_color(self):
        return self.color
    def set_color(self, color):
        self.color = color

cookie_one = Cookie('green')
cookie_two = Cookie('blue')

print('Cookie one is', cookie_one.get_color())
print('Cookie two is', cookie_two.get_color())

cookie_one.set_color('yellow')

print('\nRight now,cookie one is', cookie_one.get_color())
print('Still, cookie two is', cookie_two.get_color())

class LinkedList:
    def __init__(self, value):

    def append(self, value):

    def pop(self):

    def prepend(self, value):

    def insert(self, index, value):

    def remove(self, index):

num1 = 11
num2 = num1

print("Before value is updated:")
print("num1 =", num1)
print("num2 =", num2)

num1 = 22
# add this ↓, result is different 
# num2 = num1

print("\nAfter value is updated:")
print("num1 =", num1)
print("num2 =", num2)

dict1 = {
    'value':11
}

dict2 = dict1

print('Before value is updated:')
print("dict1 =", dict1)
print("dict2 =", dict2)

dict1['value'] = 22
# add this ↓, result is same
# dict2 = dict1

print('\nAfter value is updated:')
print("dict1 =", dict1)
print("dict2 =", dict2)

// head has a value

head: {
? ? "value": 11,
? ? "next": {
? ? ? ? "value": 3,
? ? ? ? "next": {
? ? ? ? ? ? "value": 23,
? ? ? ? ? ? "next": {
? ? ? ? ? ? ? ? "value": 7,
? ? ? ? ? ? ? ? "next": None
? ? ? ? ? ? }
? ? ? ? }
? ? }
}

print(head['next']['next']['value'])
# output: 23

print(head['value'])
# output: 11

print(head['next'])
# outlput: {'value': 3, 'next': {'value': 23, 'next': {'value': 7, 'next': None}}}

# a Node

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None

# create new Node

class LinkedList:
    def __init__(self, value):
        create new Node
    def append(self, value):
        create new Node
        add Node to end
    # def pop(self):

    def prepend(self, value):
        create new Node
        add Node to beginning
    def insert(self, index, value):
        create new Node
        insert Node
    def remove(self, index):

# head is the first node

class Node:
    def __init__(self, value):
        self.value = value
        self.next = None


class LinkedList:
    def __init__(self, value):
        new_node = Node(value)
        self.head = new_node
        self.tail = new_node
        self.length = 1

my_linked_list = LinkedList(4)

print(my_linked_list.head.value)
# output: 4

def print_list(self):
    temp = self.head
    while temp is not None:
        print(temp.value)
        temp = temp.next

# head does not have a value

head = {
    "value": None
    "next": None
}

print(head['value'])
# output: None

print(head['next'])
# output: None