Leetcode 371. Sum of Two Integers. C++ / Java

371. Sum of Two Integers 

Given two integers a and b, return the sum of the two integers without using the operators + and -.

 

Example 1:

Input: a = 1, b = 2
Output: 3

Example 2:

Input: a = 2, b = 3
Output: 5

 

Constraints:

• -1000 <= a, b <= 1000

Solution : 

C++ :

class Solution {
public:
    int getSum(int a, int b) {
        if (b==0) return a;
        int sum = a ^ b;
        int cr = (unsigned int) (a & b) << 1;
        return getSum(sum, cr);
        
        
    }
};

Java : 

class Solution {
    public int getSum(int a, int b) {
                while(b != 0){
        int tmp = (a & b) << 1;
        a = a ^ b;
        b = tmp;
    }
    return a;
    }
}

Explaination :