import java.util.ArrayList;

 import java.util.Collections;

 import java.util.Iterator;

 import java.util.TreeSet;

 public class test {

         public static  void main(String[] args) {

             String input = "aavzcadfdsfsdhshgwasdfasdfddaaa";

             new test().doString(input);

     }

     public void doString(String input){

         char[] chars = input.toCharArray();

         ArrayList<String> lists = new ArrayList<String>();

         // 第一步:先将数组传入到TreeSet,通过这个集合自动过滤掉重复的字母，并且该集合会自动排序。

         TreeSet<String> set = new TreeSet<String>();

         for(int i=0;i<chars.length;i++){

             lists.add(String.valueOf(chars[i]));

             set.add(String.valueOf(chars[i]));

         }

         System.out.println(set);//输出:[a, c, d, f, g, h, s, v, w, z]

         Collections.sort(lists);// 第二步:使用ArrayList 进行快速排序

         System.out.println(lists);//输出:[a, a, a, a, a, a, a, a, c, d, d, d, d, d, d, d, f, f, f, f, g, h, h, s, s, s, s, s, v, w, z]

         StringBuffer sb = new StringBuffer();

         for(int i=0;i<lists.size();i++){

             sb.append(lists.get(i));

         }

         input = sb.toString();

         System.out.println(input);//输出:aaaaaaaacdddddddffffghhsssssvwz

         int max = 0;

         String maxString = "";

         ArrayList<String> maxList = new ArrayList<String>();

         Iterator its = set.iterator();

         while(its.hasNext()){

             String os = (String) its.next();

             int begin = input.indexOf(os);

             int end = input.lastIndexOf(os);// 第三步:使用indexOf 和 lastIndexOf 来求出最大值。

             int value = end - begin +1;

             if(value>max){

                 max = value;

                 maxString = os;

                 maxList.add(os);

             }else if(value==max){

                 maxList.add(os);

             }

         }

         System.out.println("maxString:"+maxString);//输出:maxString:a

         System.out.println("maxList:"+maxList);//输出:maxList:[a]

         int index = 0;

         for(int i=0;i<maxList.size();i++){

             if(maxList.get(i).equals(maxString)){

                 index = i;

                 break;

             }

         }

         System.out.print("max data:");//输出:max data:a

         for(int i=index;i<maxList.size();i++){

             System.out.println(maxList.get(i)+" ");

         }

         System.out.println();

         System.out.println("max:"+max);//输出:max:8

         }    

 }