题解 | #出现一次的牛#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型一维数组 
     * @return int整型
     */
    public int findSingleCow (int[] nums) {
        Arrays.sort(nums);

        int left = 0;
        int right = left + 2;
        int res = -1;

        if(nums[nums.length-1]!=nums[nums.length-2])
            res = nums[nums.length-1];
        else
            while(right<=nums.length-1){

                if(nums[left]==nums[right]){
                    left = left + 3;
                    right = left + 2;
                }else{
                    res = nums[left];
                    break;
                }
            }
        
        return res;
    }
}