public class Solution {
/**
 * @param nums a list of integer
 * @return void
 */
public void wiggleSort(int[] nums) {
    // Write your code here
    int length = nums.length;
    for (int i = 1; i < length; i++) {
        if (i % 2 == 0) {
            if (nums[i] > nums[i - 1]) {
                swap(nums, i , i - 1);
            }
        } else {
            if (nums[i] < nums[i - 1]) {
                swap(nums, i, i - 1);
            }
        }
    }
}

private void swap(int[] nums, int a, int b) {
    nums[a] = nums[a] ^ nums[b];
    nums[b] = nums[a] ^ nums[b];
    nums[a] = nums[a] ^ nums[b];
}
}