How to find if a number is perfect square

Check out my latest post on How to find if a number is perfect square on my new blog on Programming Interviews Series.

Comments

• Anonymous
  May 30, 2011
  Why not use sqrt, or its iterative formula?

• Anonymous
  May 30, 2011
  You can calculate prime factor of No. and if prime factors are even then No. is perfect square.

• Anonymous
  May 31, 2011
        static bool IsSquareNumber(long num)        {            if (num < 0)            {                return false;            }            if (num == 0)            {                return true;            }            long s1 = -1;            long s2 = -1;            long s3 = 1;            do            {                s1 = s2;                s2 = s3;                s3 = (s2 + num / s2) / 2;                Console.WriteLine(" {0}", s3);            }            while (s1 != s3);            return (s1 * s1 == num) || (s2 * s2 == num);        }