Given an array of integers, every element appears three times except for one. Find that single one.

代码如下：

 1 public class Solution {
 2     public int singleNumber(int[] nums) {
 3         if(nums.length==1||nums.length==2)
 4         return nums[0];
 5         Arrays.sort(nums);
 6         for(int i=0;i<nums.length-2;)
 7         {
 8             if(nums[i]==nums[i+1]&&nums[i]==nums[i+2])
 9             i=i+3;
10             else return nums[i];
11         }
12         return nums[nums.length-1];
13     }
14 }