Min Stacks

The lecture covers the concept of a min stack, a data structure that supports standard stack operations like push, pop, and top, along with an additional operation to retrieve the minimum element in constant time. The instructor explains the basic stack operations and introduces the get min functionality, which allows for efficient retrieval of the minimum element. The lecture also discusses the design of a min stack using an auxiliary stack to keep track of minimum values, ensuring constant time complexity for all operations.

What is the primary function of the 'push' operation in a stack?

• To sort the stack

• To remove the top item

• To view the top item

• To add an item to the stack

In a stack, what does the 'pop' operation do?

• Removes the top item

• Duplicates the top item

• Removes the bottom item

• Adds an item to the stack

What is the result of the 'top' operation in a stack?

• The bottom item

• The middle item

• The top item

• The smallest item

What additional functionality does a min stack provide?

• It allows sorting of elements

• It retrieves the minimum element efficiently

• It duplicates the stack

• It reverses the stack

How does the 'get min' operation work in a min stack?

• It retrieves the maximum element

• It retrieves the last element

• It retrieves the minimum element

• It retrieves the middle element

What is the main challenge addressed by the min stack?

• Reversing the stack

• Finding the maximum element

• Sorting the stack

• Maintaining the minimum element efficiently

What is the time complexity goal for retrieving the minimum element in a min stack?

• O(n)

• O(log n)

• O(1)

• O(n^2)

What is the purpose of maintaining a separate min stack?

• To store the average values

• To store the minimum values at each step

• To store the sum of values

• To store the maximum values

When a new element is pushed onto the stack, what happens in the min stack?

• The element is ignored

• The element is added if it's a new minimum

• The element is always added

• The element is removed

What happens to the min stack when the minimum element is popped from the main stack?

• The min stack is duplicated

• The min stack is cleared

• The min stack remains unchanged

• The previous minimum is restored