import java.lang.String;

/**
 * implements a trie for storing strings/string prefixes
 *
 * @author Owen Astrachan
 * @version $Id: Trie.java,v 1.1 1996/12/01 00:07:21 ola Exp ola $
 *
 */


public class Trie
{
    /**
     *  create a new Trie (characters a-z)
     */
    
    public Trie()
    {
	myLinks = new Trie[ALPH];
	myIsWord = false;
    }

    /**
     * Add a string to the trie
     *
     * @param s The string added to Trie
     */
    
    public void addString(String s)
    {
	Trie t = this;
	int k;
	int limit = s.length();
	for(k=0; k < limit; k++)
	{
	    int index = s.charAt(k) - 'a';
	    if (t.myLinks[index] == null)
	    {
		t.myLinks[index] = new Trie();
	    }
	    t = t.myLinks[index];
	}
	t.myIsWord = true;
    }

    public void addCString(char s[])
    {
	Trie t = this;
	int k=0;
	while (s[k] != '\0')
	{
	    int index = s[k] - 'a';
	    if (t.myLinks[index] == null)
	    {
		t.myLinks[index] = new Trie();
	    }
	    t = t.myLinks[index];
	    k++;
	}
	t.myIsWord = true;
    }

    /**
     * print every word in the trie, one per line
     *
     */
    
    public void Print()
    {
	//DoPrint("",this);
	apply(new PrintRecorder());
    }

    public void apply(Recorder rec)
    {
	char[] buffer = new char[BUFSIZ];	 
	doApply(rec,0,buffer,this);
    }

    private void doApply(Recorder rec, int index, char buffer[], Trie t)
    {
	if (t != null)
	{
	    if (t.myIsWord)
	    {
		rec.record(new String(buffer,0,index));
	    }
	    int k;
	    for(k=0; k < ALPH; k++)
	    {
		if (t.myLinks[k] != null)
		{
		    buffer[index] = (char)(k+'a');
		    doApply(rec,index+1,buffer,t.myLinks[k]);
		}
	    }
	}	    
    }

    void DoPrint(String s, Trie t)   // now superflous (see doApply)
    {
	if (t != null)
	{
	    if (t.myIsWord)
	    {
		System.out.println(s);
	    }
	    int k;
	    for(k=0; k < ALPH; k++)
	    {
		if (t.myLinks[k] != null)
		{
		    DoPrint(s + (char)(k+'a'),t.myLinks[k]);
		}
	    }
	}
    }

    /**
     * determine if a word is in the trie (here or below)
     *
     * @param s The string searched for
     * @return true iff s is in trie (rooted here)
     */
    
    public boolean isWord(String s)
    {
	Trie t = this;
	int k;
	int limit = s.length();
	for(k=0; k < limit; k++)
	{
	    int index = s.charAt(k) - 'a';
	    if (t.myLinks[index] == null) return false;
	    t = t.myLinks[index];
	}
	return t.myIsWord;
    }

    /**
     * @return true iff path from some root to this node is a word
     * 
     */
    
    public boolean isWord()
    {
	return myIsWord;
    }

    /**
     * @param ch Character used to index node (find child)
     * @return Trie formed from this by indexing using ch
     */
    
    Trie childAt(char ch)
    {
	return myLinks[ch-'a'];
    }

    private static final int ALPH = 26;
    private static final int BUFSIZ = 1024;
    private Trie[]  myLinks;
    private boolean myIsWord;
}

class PrintRecorder implements Recorder
{
    public void record(Object o)
    {
	System.out.println(o);
    }

    public void report()
    {
	// nothing to do here
    }
}