stumped on a Java interview, need some hints

Question

This is an interview problem that I am stuck on:

Given a string consisting of a, b and c\'s, we can perform the following operation: Take any two adjacent

Answer 1

This is one of the sample questions on InteviewStreet. I tried solving it in Java and my code produces the expected results for the three test cases given, but then only passes one of the ten actual test cases. I'm a lot rusty in programming and in Java but this is what I came up with to solve the three given examples...

I can't get the code formatting just right...

import java.io.*;
import java.util.Scanner;
public class Solution
{
    public String transform(String input)
    {
        String output = new String(input);
        // System.out.println(input);
        if(output.length() > 1)
        {
            int i = 0;
            while (i < (output.length() - 1))
            {
                if(output.charAt(i) != output.charAt(i+1))
                {
                    StringBuffer sb = new StringBuffer();
                    if (output.charAt(i) == 'a')
                    {
                        // next character is b or c
                        if (output.charAt(i+1) == 'b')
                        {
                            sb.append('c');
                        }
                        else
                        {
                            sb.append('b');
                        }
                    }
                    else if (output.charAt(i) == 'b')
                    {
                        // next character is a or c
                        if (output.charAt(i+1) == 'a')
                        {
                            sb.append('c');
                        }
                        else
                        {
                            sb.append('a');
                        }
                    }
                    else
                    {
                        // next character is a or b
                        if (output.charAt(i+1) == 'a')
                        {
                            sb.append('b');
                        }
                        else
                        {
                            sb.append('a');
                        }
                    }
                    String remainder = output.substring(i+2);
                    if (remainder.length() > 0)
                    {
                        sb.append(remainder);
                    }
                    Solution anotherAnswer = new Solution();
                    output = anotherAnswer.transform(sb.toString());

                } 
                i++;
            }
        }

        return output;
    }


    /**
     * @param args
     * @throws Exception 
     */
    public static void main(String[] args) throws Exception
    {
        // TODO Auto-generated method stub
        Scanner sc;
        try
        {
            sc = new Scanner(new BufferedReader(new FileReader("input.txt")));
            // sc = new Scanner(System.in);
            int numberOfTests = sc.nextInt();
            for (int i = 1; i <= numberOfTests; i++)
            {
                String testData = sc.next();
                Solution answer = new Solution();
                String transformedData = answer.transform(testData);
                System.out.println(transformedData.length());
            }
        }
        catch (Exception e) 
        {
            throw new Exception(e);
        }
    }

}