You are given three independent interview prompts. 1) **Code comprehension & complexity** - Given two short code snippets (language-agnostic), explain in plain English what each snippet does. - Analyze **time complexity** and **space complexity** (Big-O). State any assumptions (e.g., input size, data structure costs). 2) **Object-oriented design: Jigsaw puzzle** Design the core classes and APIs for a jigsaw puzzle application. - Pieces can be rotated. - Each piece has 4 sides that must match adjacent pieces. - The board supports placing, removing, and validating placements. - Describe key classes, relationships, and important methods. You may include high-level pseudocode. 3) **Object-oriented design: 2048 game** Design the core logic and data model for the 2048 game. - 4x4 grid of tiles with values (2,4,8,...). - A move (up/down/left/right) slides tiles and merges equal adjacent tiles once per move. - After a valid move, spawn a new tile (usually 2 or sometimes 4) in an empty cell. - Track score and detect game-over. - Provide classes/data structures and the algorithm to process a move.