Spiral Matrix

Medium

Given an m x n matrix, return all elements in spiral order (clockwise starting from the top-left).

Example 1

Input:  matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,2,3,6,9,8,7,4,5]

Example 2

Input:  matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]

Constraints

• 1 <= m, n <= 10
• -100 <= matrix[i][j] <= 100