Code Room
CodingMediumcod-g432
Subject In place transformsLevel Mid–Senior~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Rotate an n x n matrix 90 degrees COUNTER-clockwise in place (no extra matrix allocation) and return it. The matrix is square with n up to 100. Note: counter-clockwise is the less common direction, so be careful with the reflection order.

Implement
rotate_ccw(matrix: list[list[int]]) → list[list[int]]
Examples
in[[[1,2,3],[4,5,6],[7,8,9]]]out[[3,6,9],[2,5,8],[1,4,7]]
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.