CodeEval - Text to Number - Hard

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws FileNotFoundException, IOException {

        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer();
        String line;
        HashMap<String,Integer> lessThan1000=getLessThan1000();
        while ((line = in.readLine()) != null) {
            StringTokenizer st=new StringTokenizer(line);
            String[]arr=new String[st.countTokens()];
            for(int i=0;i<arr.length;i++){
                arr[i]=st.nextToken();
            }
            sb.append(convToNum(arr, lessThan1000));
            sb.append('\n');
        }
        System.out.print(sb);
    }
  
    static int convToNum(String[]arr,HashMap<String,Integer> hm){
        int val=0;
        LinkedList<String> digit=new LinkedList<String>();
        LinkedList<String> thousand=new LinkedList<String>();
        LinkedList<String> million=new LinkedList<String>();
        int cases=0;
        boolean neg=false;
        for(int i=arr.length-1;i>-1;i--){
            if(arr[i].equals("thousand")){
                cases=1;
            }
            else if(arr[i].equals("million")){
                cases=2;
            }else{
                if(i==0){
                    if(arr[0].equals("negative")){
                        neg=true;
                        continue;
                    }
                }
                if(cases==0){
                    digit.add(arr[i]);
                }else if(cases==1){
                    thousand.add(arr[i]);
                }else{
                    million.add(arr[i]);
                }
            }
        }
        val=getVal(million, hm)*1000*1000+getVal(thousand, hm)*1000+getVal(digit, hm);
        if(neg){
            val=-val;
        }
        return val;
    }
  
    static int getVal(LinkedList<String> list,HashMap<String,Integer> hm){
        boolean first=true;
        StringBuilder sb=new StringBuilder();
        if(list.isEmpty()){
            return 0;
        }
        while(!list.isEmpty()){
            if(!first){
                sb.append(' ');
            }
            sb.append(list.removeLast());
            first=false;
        }
        return hm.get(sb.toString());
    }
  
    static HashMap<String, Integer> getLessThan1000(){
        HashMap<String,Integer> hm=new HashMap<String, Integer>();
        HashMap<String,Integer> digits0=initDigits0();
        HashMap<String,Integer> digits1=initDigits1();
        HashMap<String,Integer> digits2=initDigits2();
        for(String s:digits0.keySet()){
            hm.put(s,digits0.get(s));
        }
        for(String s:digits1.keySet()){
            hm.put(s,digits1.get(s));
        }
        digits0.remove("zero");
        for(String s:digits2.keySet()){
            hm.put(s,digits2.get(s));
            for(String s2:digits0.keySet()){
                hm.put(s+" "+s2,digits2.get(s)+digits0.get(s2));
            }
        }
        for(String s0:digits0.keySet()){
            hm.put(s0+" hundred",digits0.get(s0)*100);
            for(String s:digits0.keySet()){
                hm.put(s0+" hundred "+s,digits0.get(s0)*100+digits0.get(s));
            }
            for(String s:digits1.keySet()){
                hm.put(s0+" hundred "+s,digits0.get(s0)*100+digits1.get(s));
            }
            for(String s:digits2.keySet()){
                hm.put(s0+" hundred "+s,digits0.get(s0)*100+digits2.get(s));
                for(String s2:digits0.keySet()){
                    hm.put(s0+" hundred "+s+" "+s2,digits0.get(s0)*100+digits2.get(s)+digits0.get(s2));
                }
            }
        }
        return hm;
    }
  
    static HashMap<String, Integer> initDigits0(){
        HashMap<String,Integer> hm=new HashMap<String, Integer>();
        hm.put("zero",0);
        hm.put("one",1);
        hm.put("two",2);
        hm.put("three",3);
        hm.put("four",4);
        hm.put("five",5);
        hm.put("six",6);
        hm.put("seven",7);
        hm.put("eight",8);
        hm.put("nine",9);
        return hm;
    }
  
    static HashMap<String, Integer> initDigits1(){
        HashMap<String,Integer> hm=new HashMap<String, Integer>();
        hm.put("ten",10);
        hm.put("eleven",11);
        hm.put("twelve",12);
        hm.put("thirteen",13);
        hm.put("fourteen",14);
        hm.put("fifteen",15);
        hm.put("sixteen",16);
        hm.put("seventeen",17);
        hm.put("eighteen",18);
        hm.put("nineteen",19);
        return hm;
    }
  
    static HashMap<String, Integer> initDigits2(){
        HashMap<String,Integer> hm=new HashMap<String, Integer>();
        hm.put("twenty",20);
        hm.put("thirty",30);
        hm.put("forty",40);
        hm.put("fifty",50);
        hm.put("sixty",60);
        hm.put("seventy",70);
        hm.put("eighty",80);
        hm.put("ninety",90);
        return hm;
    }
  
}