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In-Place Transpose & ReverseSolved Nov 8, 2025
Problem
Given a 2D square matrix, rotate it by 90 degrees clockwise. The note suggests solving this in-place (without using a second N × N matrix).
Reading the solution first feels like progress, but it makes the next similar problem — and the interview version — much harder, because you skipped the part where you figure it out. Give it an honest 20–30 minutes. Stuck? Re-read the pattern, watch the concept video, or try the brute force first.
Hidden: approach · step-by-step visual · solution code