Knew the base problem cold so I jumped straight into the recursion.
First, clarify the specific modification to the classic parentheses generation problem, as it could involve different constraints like unique combinations, balanced parentheses with wildcards, or additional characters. Then, outline a backtracking approach that builds the string incrementally while maintaining validity, and discuss how the modification affects the algorithm's logic and complexity.
Pro tip: Demonstrate awareness of Netflix's engineering culture by emphasizing scalability and efficiency: mention how your solution can handle large n without excessive memory usage, and discuss potential optimizations like pruning invalid branches early.
Ask the interviewer to specify the exact modification to the classic problem, as it could involve different constraints (e.g., unique combinations, additional characters, or different validity rules). This ensures you solve the correct problem.
Describe a recursive backtracking algorithm that builds the parentheses string character by character, ensuring at each step that the number of closing parentheses does not exceed opening ones. Explain how the modification changes the validity condition or pruning logic.
Discuss the time and space complexity (e.g., Catalan number for classic case) and how the modification affects it. Mention potential optimizations like memoization or iterative solutions if applicable.
Identify edge cases such as n=0, n=1, or invalid inputs, and explain how your solution handles them. Walk through a small example to validate the approach.
If asked, write clean code for the solution, and discuss trade-offs between different approaches (e.g., recursion vs. iteration, memory usage).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.