Describe the main operations for data structures…

Stack

A stack is a data structure that operates on the LIFO (Last-In, First-Out) principle, where the last added element is the first to be removed.

Main operations:

Push: Add an element to the top of the stack.

# Example of push operation in Python using a list
stack = []
stack.append(10) # Add element
stack.append(20)
# Now the stack: [10, 20] (20 on top)

Pop: Remove and return the element from the top of the stack. If the stack is empty, the operation may raise an error.
```
# Example of pop operation
element = stack.pop() # Remove element (20)
# Now the stack: [10]
# element == 20
```

Peek (or Top): Return the element from the top of the stack without removing it.

# Example of peek operation
if stack: # Check if the stack is not empty
    top_element = stack[-1]
    # top_element == 10
    # The stack remains unchanged: [10]

IsEmpty: Check if the stack is empty.

# Example of is_empty operation
is_empty = len(stack) == 0
# is_empty == False in this case
empty_stack = []
is_empty_empty = len(empty_stack) == 0
# is_empty_empty == True

Queue

A queue is a data structure that operates on the FIFO (First-In, First-Out) principle, where the first added element is the first to be removed.

Main operations:

Enqueue: Add an element to the end of the queue.

# Example of enqueue operation in Python using collections.deque
from collections import deque

queue = deque()
queue.append(10) # Add element to the end
queue.append(20)
# Now the queue: deque([10, 20]) (10 at the front, 20 at the end)

Dequeue: Remove and return the element from the front of the queue. If the queue is empty, the operation may raise an error.

# Example of dequeue operation
element = queue.popleft() # Remove element from the front (10)
# Now the queue: deque([20])
# element == 10

Front (or Peek): Return the element from the front of the queue without removing it.

# Example of front operation
if queue: # Check if the queue is not empty
    front_element = queue[0]
    # front_element == 20
    # The queue remains unchanged: deque([20])

IsEmpty: Check if the queue is empty.

# Example of is_empty operation
is_empty = len(queue) == 0
# is_empty == False in this case
empty_queue = deque()
is_empty_empty = len(empty_queue) == 0
# is_empty_empty == True

Describe the main operations for data structures: stack and queue.

Stack

Main operations:

Queue

Main operations: