59. Spiral Matrix II

Medium

Given a positive integer n, generate an n x n matrix filled with elements from 1 to n2 in spiral order.

Example 1:

Input: n = 3

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

Example 2:

Input: n = 1

Output: [[1]]

Constraints:

• 1 <= n <= 20