Given an integer n, an alternating permutation is a permutation of the first n positive integers such that no two adjacent elements are both odd or both even.
Return all such alternating permutations sorted in lexicographical order.
Example 1:
Input: n = 4
Output: [[1,2,3,4],[1,4,3,2],[2,1,4,3],[2,3,4,1],[3,2,1,4],[3,4,1,2],[4,1,2,3],[4,3,2,1]]
Example 2:
Input: n = 2
Output: [[1,2],[2,1]]
Example 3:
Input: n = 3
Output: [[1,2,3],[3,2,1]]
Constraints:
1 <= n <= 10Loading editor...
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