Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.
Example:
Given a = 1 and b = 2, return 3.
用 异或 表示sum，与 表示 carry，carry左移一位后，递归调用getSum(sum,carry<<1)
一刷：
public int getSum(int a, int b) {
return b ==0 ? a:getSum( a^b , (a&b)<<1 );
}
[leetcode] 371. Sum of Two Integers 解题报告
原文：http://www.cnblogs.com/pulusite/p/5840489.html