Given an n x n 2D matrix representing an image, rotate it 90 degrees clockwise in place (without using another matrix).
For example:
Input: Output: 1 2 3 7 4 1 4 5 6 -> 8 5 2 7 8 9 9 6 3
Explain your approach for rotating in place, describe the pattern of how elements move, and analyze the time and space complexity.
How to approach it
- Hint 1
A 90-degree clockwise rotation can be decomposed into two simpler operations on the matrix. What are they?
- Hint 2
Try transposing the matrix (swap rows and columns) and then reversing each row.
- Hint 3
Alternatively, think about rotating in layers -- the outermost ring first, then the next ring inward.
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