324. Wiggle Sort II

Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]....

Example 1:

Input: nums = [1, 5, 1, 1, 6, 4]
Output: One possible answer is [1, 4, 1, 5, 1, 6].

Example 2:

Input: nums = [1, 3, 2, 2, 3, 1]
Output: One possible answer is [2, 3, 1, 3, 1, 2].

Note:
You may assume all input has valid answer.

Follow Up:
Can you do it in O(n) time and/or in-place with O(1) extra space?

class Solution {
    public void wiggleSort(int[] nums) {
        int[] val = Arrays.copyOf(nums, nums.length);
        Arrays.sort(val);
        int idx = val.length - 1;
        for(int i = 1;i < nums.length;i += 2) nums[i] = val[idx--];
        for(int i = 0;i < nums.length;i += 2) nums[i] = val[idx--];
    }
}

https://leetcode.com/problems/wiggle-sort-ii/discuss/266483/Two-clear-Java-solutions-with-brief-explanation-and-one-more-interesting-question