題目:
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
Could you do this in-place?
思路:
首先,要求原地調整,那麼需要尋找變換規律。舉個例子:
對於3x3的矩陣,如順時針調整(0,0)->(0,2)->(2,2)->(2,0)
對於4x4的矩陣,如順時針調整(0,0)->(0,3)->(3,3)->(3,0);(0,1)->(1,3)->(3,2)->(2,0);(0,2)->(2,3)->(3,1)->(1,0).
轉換傳遞規律:對於一個nxn矩陣來說,(a,b)->(b,n-1 - a),並且該鏈式傳遞轉換有......
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