这个是我的，有问题。
给一个用例 aaaaaa，这就错了
import java.io.*;
import java.util.*;



class Main {
  public static void main(String[] args)
  {
  	 // System.out.println(solution("abba"));  
      //  System.out.println(solution("aba"));  
      //System.out.println(solution("ababa"));  
      //System.out.println(solution("bab"));  
      System.out.println(solution("bababb"));  
      System.out.println(solution("ababaa"));  
  }
    
	public static boolean solution(String str)
    {
        int left = str.indexOf("a");
        int right  = str.lastIndexOf("a");
        int count = 0;
        while(str.charAt(left) == str.charAt(right) && left <= right)
        {
        	if(left == right)
            {
            	return false;        
            }
            left ++;
            right--;
            count++;
            if(count == 2)
            {
            	return true;        
            }
          
        }
        
        return true;
    }
    
}