[Algorithm] 1. A+B Problem

Description

Write a function that add two numbers A and B.

Clarification

Are a and b both 32-bit integers?

• Yes.

Can I use bit operation?

• Sure you can.

Example

Given a=1 and b=2 return 3.

Challenge

Of course you can just return a + b to get accepted. But Can you challenge not do it like that?(You should not use + or any arithmetic operators.)

My Answer

Using a recursion method to solve this problem!

    /**
     * @param a: An integer
     * @param b: An integer
     * @return: The sum of a and b 
     */
    int aplusb(int a, int b) {
        // Recursion process
        if ( (a & b) == 0 ){
            return a ^ b;
        } else {
            return aplusb( (a^b), ((a&b)<<1) );
        }
    }

Tips

It`s not the only way to get the right answer. Can you try the other way like the loop structure?