leetcode 面試題 01.07. 旋轉矩陣

面試題 01.07. 旋轉矩陣

難度中等87

給你一幅由 N × N 矩陣表示的圖像，其中每個像素的大小爲 4 字節。請你設計一種算法，將圖像旋轉 90 度。

不佔用額外內存空間能否做到？

 

示例 1:

給定 matrix = 
[
  [1,2,3],
  [4,5,6],
  [7,8,9]
],

原地旋轉輸入矩陣，使其變爲:
[
  [7,4,1],
  [8,5,2],
  [9,6,3]
]

示例 2:

給定 matrix =
[
  [ 5, 1, 9,11],
  [ 2, 4, 8,10],
  [13, 3, 6, 7],
  [15,14,12,16]
], 

原地旋轉輸入矩陣，使其變爲:
[
  [15,13, 2, 5],
  [14, 3, 4, 1],
  [12, 6, 8, 9],
  [16, 7,10,11]
]

 

class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
    
        """
 
        N = len(matrix)
        matrix_new = [[0] * N for _ in range(N)]
        for  i in range(N):
            for j in range(N):           
                matrix_new[j][N-i-1] = matrix[i][j]
        matrix[:] = matrix_new