371. Sum of Two Integers

 1 static int wing=[]()
 2 {
 3     std::ios::sync_with_stdio(false);
 4     cin.tie(NULL);
 5     return 0;
 6 }();
 7 
 8 class Solution 
 9 {
10 public:
11     int getSum(int a, int b) 
12     {
13         return b==0?a:getSum(a^b, (a&b)<<1);
14     }
15 };

就是位操作，原理描述起来有点费劲，自行百度吧