280. Wiggle Sort

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

Example:

Input: nums = [3,5,2,1,6,4]
Output: One possible answer is [3,5,1,6,2,4]

Solution

當i是偶數時，nums[i] <= nums[i+1]

當i是奇數時，nums[i] >= nums[i+1]

class Solution {
    public void wiggleSort(int[] nums) {
        for(int i = 0; i < nums.length-1; i++){   
            if(i % 2 == 0){
                //偶數
                if(nums[i] > nums[i+1]){
                    int temp = nums[i+1];
                    nums[i+1] = nums[i];
                    nums[i] = temp;
                }
            }
            else{
                //奇數
                if (nums[i] < nums[i+1]){
                    int temp = nums[i+1];
                    nums[i+1] = nums[i];
                    nums[i] = temp;
                }
            }
        }
    }
}