Understanding Stacks and Queues

What is the time complexity of push and pop operations in a stack?

• O(n^2)

• O(1)

• O(log n)

• O(n)

Describe the main difference between a stack and a queue.

• Both stack and queue use LIFO order.

• A stack uses FIFO order while a queue uses LIFO order.

• The main difference is that a stack uses LIFO order while a queue uses FIFO order.

• A stack allows random access while a queue does not.

How can you determine if parentheses in an expression are balanced?

• Count the number of parentheses in the expression.

• Check if the first character is an opening parenthesis.

• Ensure all parentheses are in pairs without nesting.

• Use a stack to track opening and closing parentheses.

What is the result of evaluating the postfix expression '5 6 2 + *'?

• 30

• 40

• 12

• 50

Explain how a circular queue differs from a regular queue.

• A circular queue can only hold a fixed number of elements, while a regular queue can grow dynamically.

• A circular queue allows for efficient space utilization by wrapping around, while a regular queue can lead to wasted space as it does not reuse freed slots.

• A circular queue processes elements in a last-in, first-out manner, unlike a regular queue which is first-in, first-out.

• A circular queue requires more memory than a regular queue due to its structure.

What operation would you use to add an element to the front of a DeQueue?

• prependElement

• insertFirst

• pushFront

• addFirst

In what scenario would you prefer using a stack over a queue?

• When you need First In First Out (FIFO) access to elements.

• When you want to access elements in a random order.

• When you need Last In First Out (LIFO) access to elements.

• When you need to process elements in a priority order.

What is the postfix equivalent of the infix expression '(A + B) * C'?

• A C * B +

• C * A + B

• B A + C *

• A B + C *

How do you evaluate a postfix expression using a stack?

• Use a stack to evaluate the expression by pushing numbers and applying operators.

• Evaluate by reading from right to left without using a stack.

• Only apply operators without pushing numbers onto the stack.

• Use a queue instead of a stack for evaluation.

List one real-world application of queues.

• Data storage

• Network routing

• Task scheduling

• Print spooling