Here’s the clean summary — no code, just concepts:
🔁 Transpose
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Swap matrix[r][c] with matrix[c][r]
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Reflects matrix across the main diagonal
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Rows become columns
🔄 Row Reverse
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Reverse elements inside each row
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Flips matrix left ↔ right
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Horizontal flip
🔄 Column Reverse
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Reverse elements inside each column
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Flips matrix top ↔ bottom
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Vertical flip
🔄 Rotations (NxN Matrix)
✅ 90° Clockwise
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Transpose
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Then reverse each row
✅ 180°
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Reverse rows (top ↔ bottom)
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Then reverse each row
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Order does not matter
✅ 270° Clockwise (same as 90° CCW)
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Transpose
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Then reverse each column
🧠 Mental Shortcut
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Transpose = diagonal flip
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Row reverse = horizontal flip
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Column reverse = vertical flip
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Combine flips to get rotation
That’s the whole rotate-matrix game.