Simulate infection spreading across a 2D grid with multi-source BFS, passing staged test cases.
The rotting-oranges family of build screens: a state expands outward one step per tick across a grid, with the spec adding rules each round. The signal is multi-source BFS processed by layers, not per-cell loops. Here is the design that absorbs each new test case.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
The rotting-oranges family of build screens: a state expands outward one step per tick across a grid, with the spec adding rules each round. The signal is multi-source BFS processed by layers, not per-cell loops. Here is the design that absorbs each new test case.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
