Rotate an n×n matrix 90 degrees in place.

Rotating a matrix in place probes index manipulation and the transpose-then-reverse trick. What interviewers watch for: splitting the rotation into two simple passes instead of juggling four-way swaps. Here is the answer.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.