PRE TEST_DSA_MIDTERMS

What does "Last-In, First-Out" (LIFO) mean in the context of stacks?

• The first element added is the first one to be removed

• The last element added is the first one to be removed

• Elements can be accessed in any order

• Elements are sorted as they are added

Which method is used to add an item to the top of a stack in Python?

• add()

• push()

• append()

• insert()

What does the pop() method do?

• Looks at the top item without removing it

• Removes the item from the top of the stack

• Checks if the stack is empty

• Adds an item to the stack

In the expression 6 4 + 9 3 - *, what is the result after evaluating the expression?

• 24

• 60

• 10

• 18

What is the purpose of the peek operation in stack?

• To remove the top item from the stack

• To check if the stack is empty

• To view the top item without removing it

• To add a new item to the stack

Which of the following is a common application of stacks?

• Sorting data

• Storing parameters and return points during program execution

• Managing database connections

• Compressing files

When converting from infix to postfix, what should be done when encountering a right parenthesis?

• Push it onto the stack

• Append it to the postfix expression

• Pop elements from the stack until a left parenthesis is encountered

• Ignore it completely

What is the first step in evaluating a postfix expression?

• Classify the token as operand or operator

• Push the first operand onto the stack

• Perform the operation immediately

• Check if the stack is empty

In Java, which method is used to check if a stack is empty?

• isEmpty()

• empty()

• checkEmpty()

• size()

Which of the following strings is a palindrome?

• apple

• level

• banana

• cherry