LeetCode 280. Wiggle Sort C#

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].

 

Solution:

Loop through, when odd index num should be greater then the previous num;

                       when even index num should be smaller then the previous num;

So if even index num is greater then the previous num then it must be greater then the previous of previous num too, so only swap once.

public class Solution {
    public void WiggleSort(int[] nums) {
        int l = nums.Length;
        for(int i=1; i<l;i++)
        {
            if(i%2==1)
            {
                if(nums[i]<nums[i-1])
                {
                    Swap(nums, i);
                }
            }
            else
            {
                if(nums[i]>nums[i-1])
                {
                    Swap(nums, i);
                }
            }
        }
    }
    public void Swap(int[] nums, int i)
    {
        int temp = nums[i-1];
        nums[i-1]=nums[i];
        nums[i] = temp;
    }
}