/**
 * https://leetcode.cn/problems/single-number-iii/
 * 
 *  nums
 * 
 * 
 * 
 * 
 *  1
 * nums = [1,2,1,3,2,5]
 * [3,5]
 * [5,3] 
 * 
 *  2
 * nums = [-1,0]
 * [-1,0]
 * 
 *  3
 * nums = [0,1]
 * [1,0]
 * 
 * 
 * - 2