Sum of Two Integers

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example 1:

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

Example 2:

Input: a = -2, b = 3
Output: 1
public class Solution {
    public int getSum(int a, int b) {
        if (a == 0)
            return b;
        if (b == 0)
            return a;
        // If we try to add in binary
        // possibilities are 0+1=1,1+0=1,0+0=0
        // BUT 1+1 = 10 , it carries over
        // now carry handles last part ,where as xor handles the first 3 parts
        while (b != 0) {
            int carry = a & b;
            a = a ^ b;
            b = carry << 1;
        }

        return a;
    }
}

Last updated