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

For example, given nums = [3, 5, 2, 1, 6, 4], one possible answer is [1, 6, 2, 5, 3, 4].

 1 public class Solution {
 2     public void WiggleSort(int[] nums) {
 3         if (nums == null
 
 || nums.Length < 2) return;
 4         
 5         for (int i = 1; i < nums.Length; i++)
 6         {
 7             if (i % 2 == 1 && nums[i - 1] > nums[i])
 8             {
 9                 var tmp = nums[i - 1];
10                 nums[i - 1] = nums[i];
11                 nums[i] = tmp;
 
12             }
13             
14             if (i % 2 == 0 && nums[i] > nums[i - 1])
15             {
16                 var tmp = nums[i - 1];
17                 nums[i - 1] = nums[i];
18                 nums[i] = tmp;
19             }
20         }
21     }
22 }

Leetcode 280: Wiggle Sort