50分求此题的简便算法

Question

在一个字符窜中找出出现次数最多的子字符串。比如：abcereab  显示结果 ab

Answer 1

最多的当然是一个字符的子串了
a,b,e

Answer 2

public static String maxCount(){
        String old = "abcereab";
        int count=0;
        ArrayList countList=new ArrayList();
        ArrayList wordList=new ArrayList();
        for(int i=0;i<old.length();i++){
            count=0;
            String oneWord=old.substring(i,i+1);
            for(int j=i;j<old.length();j++){
                if(oneWord.equals(old.substring(j,j+1))){
                    count++;
                }else{
                    break;
                }
                i=j;
            }
            countList.add(String.valueOf(count));
            wordList.add(oneWord);        }
        int index=-1;
        String maxCountValue=countList.get(0).toString();
        for(int i=0;i<countList.size();i++){
            if(Integer.parseInt(maxCountValue)<Integer.parseInt(countList.get(i).toString())){
                maxCountValue=countList.get(i).toString();
                index=i;
            }
        }
        String ret=countList.get(index).toString()+","+wordList.get(index);
        return ret;
    }

Answer 3

虽然在X里出了EX，不过思路蛮清晰的  谢了