LeetCode - 48. Rotate Image (Python)

Medium, 배열 회전하기

RunTime : 31 ms / Memory : 16.31 MB

문제

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.

풀이

• 오랜만에 본 배열 Rotate 문제, 백준에서 간간히 접했었다.
  • 근데 다 까먹어서 다시 봄

90도 회전
tmp[j][n - 1 - i] = graph[i][j]

class Solution:
    def rotate(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        n = len(matrix)

        tmp = [[0] * n for _ in range(n)]

        for i in range(n):
            for j in range(n):
                tmp[j][n - 1 - i] = matrix[i][j]
        
        for i in range(n):
            for j in range(n):
                matrix[i][j] = tmp[i][j]