UVA - 789 - Indexing

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer("");
        StringBuilder temp = new StringBuilder("");
        String m = "";
        char c = (char) br.read();
        br.readLine();
        HashSet<String> hs = new HashSet<String>();
        LinkedList<StrInd> list=new LinkedList<StrInd>();
        int counter=1;
        while ((m = br.readLine()) != null) {
            StringTokenizer st=new StringTokenizer(m);
            int n=st.countTokens();
            for(int i=0;i<n;i++){
                String strID=st.nextToken();
                StringBuilder tempS=new StringBuilder();
                for (int j = 0; j < strID.length(); j++) {
                        if (strID.charAt(j) >= 'A' && strID.charAt(j) <= 'Z') {
                            tempS.append(strID.charAt(j));
                        }
                }
                if(tempS.charAt(0)==c){
                    if(!hs.contains(tempS.toString())){
                        hs.add(tempS.toString());
                        list.add(new StrInd(tempS.toString(),counter));
                    }else{
                        for(int j=0;j<list.size();j++){
                            if(list.get(j).temp.equals(tempS.toString())){
                                list.get(j).insert(counter);
                            }
                        }
                    }
                }
            }
            counter++;
        }
        StrInd []arr=new StrInd[list.size()];
        for(int i=0;i<list.size();i++){
            arr[i]=list.get(i);
        }
        Arrays.sort(arr);
        for(int i=0;i<arr.length;i++){
            sb.append(arr[i].temp);
            sb.append(arr[i].getInd());
        }
        System.out.print(sb);
    }
}
class StrInd implements Comparable<StrInd> {
    public String temp;
    LinkedList<Integer> index;

    public StrInd(String temp,int x) {
        this.temp = temp;
        index=new LinkedList<Integer>();
        index.add(x);
    }
  
    public void insert(int i){
        if(!index.contains(i))
             index.add(i);
    }
  
    public String getInd(){
        StringBuilder sb=new StringBuilder("");
        for(int i=0;i<index.size();i++){
            sb.append(" ").append(index.get(i));
        }
        sb.append("\n");
        return sb.toString();
    }

    @Override
    public int compareTo(StrInd x) {
        return this.temp.compareTo(x.temp);
    }
}