[Programmers] 54. Spiral Matrix

Python

class Solution:
    def spiralOrder(self, matrix: List[List[int]]) -> List[int]:
        answer = []
        while matrix:
            answer += matrix.pop(0)
            if matrix and matrix[0]:
                for i in matrix:
                    answer.append(i.pop())
            if matrix:
                answer += matrix.pop()[::-1]
            if matrix and matrix[0]:
                for i in matrix[::-1]:
                    answer.append(i.pop(0))
        
        return answer