Multiply two big ints.

Question

Mike · Accepted Answer

The above code is neat; unfortunately, it does not account for *big* integers being multiplied. So, suppose we have two numbers that are close to the integer limit. What would happen when we try to multiple them?
In addition, what happens when one of the integers is negative?

Anonymous · Answer

Java Provides multiply() method for BigInteger datatype.
It can be used directly.

Prateek · Answer

public static int bitwiseMultiply(int a, int b)
        {
            if (a == 0 || b == 0)
            {
                return 0;
            }

            if (a == 1)
            {
                return b;
            }
            else if (b == 1)
            {
                return a;
            }

            int result = 0; 
            while (b >= 1)
            {
                if ((b & 1) == 1)
                {
                    result = result + a;                   

                }
                a >= 1;   
            }
            return result;
        }

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