No AI allowed, which made me slow down and actually read the code instead of pattern-matching my way through it.
Start by clarifying the grid representation and the expected behavior for empty cells, then systematically trace the code to identify where empty cells are mishandled. Propose a fix that checks for empty cells and replaces them with '*', and validate with a test case that includes both empty and non-empty cells.
Pro tip: Demonstrate defensive coding by considering edge cases like null or empty grids, and discuss the trade-offs of different fix approaches (e.g., in-place modification vs. creating a new grid).
Ask clarifying questions to confirm the grid representation (e.g., 2D array of strings, empty cell defined as null, empty string, or whitespace) and the exact expected output.
Walk through the existing function line by line, using a small example grid to identify where the logic fails to handle empty cells correctly.
Describe the change needed, such as adding a conditional check for empty cells and replacing them with '*', ensuring non-empty cells remain unchanged.
Provide a concrete test case with a grid containing both empty and non-empty cells, and show the expected output after the fix.
Mention potential edge cases (e.g., null grid, empty grid, different empty cell representations) and trade-offs of your approach (e.g., readability vs. performance).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.