【Lintcode】508. Wiggle Sort

題目地址：

https://www.lintcode.com/problem/wiggle-sort/description

參考https://blog.csdn.net/qq_46105170/article/details/106046104。代碼如下：

public class Solution {
    /*
     * @param nums: A list of integers
     * @return: nothing
     */
    public void wiggleSort(int[] nums) {
        // write your code here
        if (nums == null || nums.length < 2) {
            return;
        }
        
        for (int i = 0; i < nums.length - 1; i++) {
            if (i % 2 == 0 && nums[i] > nums[i + 1]) {
                swap(nums, i, i + 1);
            } else if (i % 2 != 0 && nums[i] < nums[i + 1]) {
                swap(nums, i, i + 1);
            }
        }
    }
    
    private void swap(int[] nums, int i, int j) {
        int tmp = nums[i];
        nums[i] = nums[j];
        nums[j] = tmp;
    }
}

時間複雜度$O(n)$，空間$O(1)$。