Interview Question for Software Engineer at Google:

101

Uh, I think you meant 201 - perhaps this is why you didn't get the job.

99 = 2 * 7 * 7 + 1 = 2 * 7 ^ 2 + 0 * 7 ^ 1 + 1 * 7 ^ 0 = 201

Here's the code that does this in general:

String convertToBase(int num, int radix)
{
      StringBuilder sb = new StringBuilder();
      int n = num / radix;
      int lsd = num % radix;
      do
      {
             sb.insert(0, lsd);
             lsd = n % radix;
             n /= radix;
      }
      while (n > 0);
      sb.insert(0, lsd);
      return sb.toString();
}