1886. Determine Whether Matrix Can Be Obtained By Rotation

Problem Link

Description

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Given two n x n binary matrices mat and target, return true if it is possible to make mat equal to target by rotating mat in 90-degree increments, or false otherwise.

 

Example 1:

Input: mat = [[0,1],[1,0]], target = [[1,0],[0,1]]
Output: true
Explanation: We can rotate mat 90 degrees clockwise to make mat equal target.

Example 2:

Input: mat = [[0,1],[1,1]], target = [[1,0],[0,1]]
Output: false
Explanation: It is impossible to make mat equal to target by rotating mat.

Example 3:

Input: mat = [[0,0,0],[0,1,0],[1,1,1]], target = [[1,1,1],[0,1,0],[0,0,0]]
Output: true
Explanation: We can rotate mat 90 degrees clockwise two times to make mat equal target.

 

Constraints:

• n == mat.length == target.length
• n == mat[i].length == target[i].length
• 1 <= n <= 10
• mat[i][j] and target[i][j] are either 0 or 1.

Solution

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Python3

class Solution:
    def findRotation(self, mat: List[List[int]], target: List[List[int]]) -> bool:
        rows, cols = len(mat), len(mat[0])
        
        def rotate(M):
            M = list(reversed(M))
            
            for i in range(rows):
                for j in range(i + 1, cols):
                    M[i][j], M[j][i] = M[j][i], M[i][j]
            
            return M
        
        for _ in range(4):
            mat = rotate(mat)
            if mat == target: return True
            
        return mat == target