You are given an n x n
2D matrix
representing an image, rotate the image by 90 degrees (clockwise).
You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[7,4,1],[8,5,2],[9,6,3]]
Example 2:
Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
Constraints:
-
n == matrix.length == matrix[i].length
-
1 <= n <= 20
-
-1000 <= matrix[i][j] <= 1000
SOLUTION:
class Solution:
def rotate(self, matrix: List[List[int]]) -> None:
n = len(matrix)
cache = {}
for i in range(n):
for j in range(n):
cache[(i, j)] = matrix[i][j]
for i in range(n):
for j in range(n):
matrix[j][n - i - 1] = cache[(i, j)]
Top comments (0)