Downward Spiral Matrix
Given a positive integer n, print an n x n matrix containing the numbers from 1 to n * n in spiral order, starting at the top-left corner and moving down.
Input
- One positive integer n.
Output
- Numbers on the same line are separated by exactly one space.
Constraints
- 1 <= n <= 30
Example
Input
4
Output
1 12 11 10
2 13 16 9
3 14 15 8
4 5 6 7
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