# ---
# title: 54. Spiral Matrix
# id: problem54
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Array
# link: <https://leetcode.com/problems/spiral-matrix/description/>
# hidden: true
# ---
# 
# Given an `m x n` `matrix`, return _all elements of the_ `matrix` _in spiral
# order_.
# 
# 
# 
# **Example 1:**
# 
# ![](https://assets.leetcode.com/uploads/2020/11/13/spiral1.jpg)
# 
#     
#     
#     Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
#     Output: [1,2,3,6,9,8,7,4,5]
#     
# 
# **Example 2:**
# 
# ![](https://assets.leetcode.com/uploads/2020/11/13/spiral.jpg)
# 
#     
#     
#     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:**
# 
#   * `m == matrix.length`
#   * `n == matrix[i].length`
#   * `1 <= m, n <= 10`
#   * `-100 <= matrix[i][j] <= 100`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
