class Stack:
    def __init__(self):
        self.stack = []

    def push(self, item):
        self.stack.append(item)

    def pop(self):
        if not self.is_empty():
            return self.stack.pop()

    def peek(self):
        if not self.is_empty():
            return self.stack[-1]

    def is_empty(self):
        return len(self.stack) == 0

    def size(self):
        return len(self.stack)
	
	# Zadanie dodatkowe
    def is_equal(self, other):
        if self.size() != other.size():
            return False
        for i in range(self.size()):
            if self.stack[i] != other.stack[i]:
                return False
        return True

stack = Stack()

stack.push(1)
stack.push(2)
stack.push(3)

print(stack.pop())  # 3
print(stack.peek())  # 2
print(stack.is_empty())  # False
print(stack.size())  # 2


# =======================================================================
class Queue:
    def __init__(self):
        self.queue = []

    def is_empty(self):
        return len(self.queue) == 0

    def enqueue(self, item):
        self.queue.append(item)

    def dequeue(self):
        if not self.is_empty():
            return self.queue.pop(0)

    def peek(self):
        if not self.is_empty():
            return self.queue[0]

queue = Queue()

queue.enqueue(1)
queue.enqueue(2)
queue.enqueue(3)

print(queue.dequeue())  # 1
print(queue.dequeue())  # 2
print(queue.is_empty())  # False
print(queue.dequeue())  # 3
print(queue.is_empty())  # True

# =======================================================================
class BrowserHistory:
    def __init__(self):
        self.history = Stack()
        self.current_page = None
 
    def go_to_page(self, url):
        self.history.push(self.current_page)
        self.current_page = url
 
    def go_back(self):
        previous_page = self.history.pop()
        if previous_page is not None:
            self.current_page = previous_page
 
    def print_history(self):
        print("Current page:", self.current_page)
        print("History:")
        for page in reversed(self.history.stack):
            print(page)

# =======================================================================
class Customer:
    def __init__(self, name, order):
        self.name = name
        self.order = order

class CinemaQueue:
    def __init__(self):
        self.queue = Queue()

    def is_empty(self):
        return self.queue.is_empty()

    def add_customer(self, customer):
        self.queue.enqueue(customer)

    def remove_customer(self):
        if not self.is_empty():
            return self.queue.dequeue()

    def next_customer_order(self):
        if not self.is_empty():
            next_customer = self.queue.peek()
            return next_customer.order

# =======================================================================
def is_palindrome(string):
    stack = Stack()
    for char in string:
        stack.push(char)
    reversed_string = ""
    while not stack.is_empty():
        reversed_string += stack.pop()
    return string == reversed_string