Virtual Labs

1. Which among the following represents a stack?

a: People waiting at a counter, where the first person served is the first person who arrived Explanation

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b: A hand of bangles where pushing is wearing a new bangle Explanation

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c: A pile of plates at a dinner party Explanation

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d: People going around a merry-go-round Explanation

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2. What is the time complexity of a push operation in a stack? What is the time complexity of a pop operation in a stack?

O(n)

O(n)

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O(1)

O(n)

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O(n)

O(1)

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O(1)

O(1)

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3. Consider these operations on an empty stack: push(3), push(5), pop(), push(10), push(11), pop(), push(100). What will be the stack configuration? The first number is the top of the stack and the last number is the bottom.

a: 100, 10, 3 Explanation

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b: 3, 5, 10, 11, 100 Explanation

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c: 3, 10, 100 Explanation

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d: 100, 11, 10, 3 Explanation

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4. If a stack is initially empty and the operations push(4), push(7), push(9), pop(), push(12) are performed, which element is at the top?

a: 4 Explanation

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b: 7 Explanation

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c: 9 Explanation

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d: 12 Explanation

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5. Which operation allows the top element of a stack to be inspected without removing it?

a: Peek Explanation

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b: Push Explanation

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c: Pop Explanation

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d: Enqueue Explanation

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6. What condition occurs when a pop operation is attempted on an empty stack?

a: Overflow Explanation

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b: Underflow Explanation

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c: Collision Explanation

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d: Traversal Explanation

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7. A stack is used to evaluate a postfix expression. Which property of the stack makes it suitable for this task?

a: It processes elements according to FIFO order Explanation

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b: It always stores elements in sorted order Explanation

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c: It provides LIFO access to operands and intermediate results Explanation

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d: It allows insertion only at the rear Explanation

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8. A stack is implemented using an array of capacity 5. If the stack already contains 5 elements, what happens when another push operation is attempted?

a: The operation causes stack overflow Explanation

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b: The operation causes stack underflow Explanation

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c: The oldest element is automatically removed Explanation

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d: The new element is inserted below the bottom element Explanation

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9. Which sequence of operations on an empty stack results in 20 being at the top while 10 remains below it?

a: push(20), push(10) Explanation

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b: push(10), pop(), push(20) Explanation

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c: push(10), push(20) Explanation

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d: push(20), pop(), push(10) Explanation

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Stacks and Queues