Keep swaping with next integer once the condition doesn't meet

```
public class Solution {
public void wiggleSort(int[] nums) {
if (nums == null || nums.length == 0) return;
boolean isEven = true;
for (int i = 0; i < nums.length - 1; i++) {
if ((isEven && nums[i] > nums[i + 1]) || (!isEven && nums[i] < nums[i + 1])) {
swap(nums, i, i + 1);
}
isEven = !isEven;
}
}
public void swap(int[] nums, int i, int j) {
int tmp = nums[i];
nums[i] = nums[j];
nums[j] = tmp;
}
}
```