Start by clarifying the requirements and constraints, then define a Node class and a DoublyLinkedList class with head and tail pointers. Implement core operations like insert, delete, and search, ensuring proper pointer updates and edge case handling, and analyze time/space complexity.
Pro tip: At Meta, interviewers value clean, bug-free code and thorough edge case testing. After implementing, walk through examples including empty list, single node, and operations at head/tail to demonstrate robustness.
Ask about expected operations (insert, delete, search), whether to support indexing, and any constraints like memory or thread safety. Confirm if sentinel nodes are allowed.
Define a Node class with value, prev, and next pointers. Define DoublyLinkedList with head and tail pointers and a size counter. Decide on sentinel nodes for simpler edge cases.
Code methods for insertion (at head, tail, or index), deletion (by value or index), and search. Ensure each method correctly updates prev/next pointers and handles empty list, single node, and boundary conditions.
Walk through test cases: empty list, insert/delete at head/tail, middle operations, and search for existing/non-existing values. Check for memory leaks (if applicable) and pointer consistency.
State time complexity for each operation (O(1) for insert/delete at known positions, O(n) for search) and space complexity O(n). Discuss trade-offs vs singly linked list.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.