leetcode 371

371. Sum of Two Integers

Total Accepted: 15459
Total Submissions: 29688
Difficulty: Easy

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.

思路：两相加，但是不能用加号和减号，那么从进位和异火等符号入手。异或计算加法，相与计算进位。

public class Solution {

    public int getSum(int a, int b) {

        if(b == 0){

            return a;

        }

        int sum = a^b;

        int carry = (a&b)<<1;

        return getSum(sum, carry);

    }

}