Business Intelligence Engineer, Data Science & Analytics

Amazon

Implement a Stack data structure using one or more Queues. Your stack should support the standard push, pop, top (peek), and empty operations. push(x):** Adds element x to the top of the stack. pop():** Removes the element on the top of the stack and returns it. top():** Returns the element on the top of the stack without removing it. empty():** Returns whether the stack is empty. For example, consider the following sequence of operations: push(1) push(2) top() // returns 2 pop() // returns 2 empty() // returns false Explain your approach clearly, focusing on how you would use queue operations (enqueue and dequeue) to achieve stack-like behavior. Discuss the time complexity of each operation in your implementation. Consider edge cases and potential optimizations.

Amazon

Let's design a turnstile. A turnstile is a type of gate which allows one person to pass at a time. Consider a turnstile at a subway station. There are two panels that rotate to allow a single person passage. The turnstile has two states, Locked and Unlocked, and the customer can either Push the turnstile or Insert a token/card. Here is the state transition table: | Event | Current State | Action | Next State | | :----- | :------------ | :------------- | :--------- | | Push | Locked | | Locked | | Token | Locked | Unlock | Unlocked | | Push | Unlocked | Pass through | Locked | | Token | Unlocked | (discarded) | Unlocked | Requirements: Model the state and behavior of a simple turnstile. Implement two methods: insert_token() push() Consider edge cases and error handling. What happens if someone tries to push without inserting a token? What happens if the system malfunctions? Example: turnstile = Turnstile() print(turnstile.state) # Output: Locked turnstile.push() print(turnstile.state) # Output: Locked turnstile.insert_token() print(turnstile.state) # Output: Unlocked turnstile.push() print(turnstile.state) # Output: Locked How would you approach this design and implementation, keeping in mind scalability, maintainability, and potential future extensions such as different types of tokens or remote unlocking?

Amazon

Tell me about yourself. To give you some guidance, please share information beyond just your resume. For example, what are you passionate about, what motivates you, and what are some of your long-term career goals? Think about some significant accomplishments you are proud of and how those experiences have shaped you. What makes you a unique candidate and a good fit for our company, beyond your technical skills? I'm looking for a comprehensive overview of who you are, both professionally and personally.