import java.io.*;
/**
   Interface for the implementation of the Trie data
   structure.
*/
public interface Trie{
  /**
     Computes the pair composed of 
     the length of the longest prefix of s[j..n-1] in the trie
     and the vertex reached by this prefix. Implements the function
     <code>LongestPrefixInTrie()</code> of Section 1.3.1.
     @param s the input string
     @param j the starting index
     @return the computed pair
  */  
    public  Pair longestPrefixInTrie(String s,int j);
    /**
       Returns true if the trie contains <code>s</code>. Implements 
       the function <code>IsInTrie()</code> of Section 1.3.1.
    */
    public boolean isInTrie(String s);
  /**
     Adds the word s to the trie. Implements 
       the function <code>AddToTrie()</code> of Section 1.3.1.
     @param s the string to be added.
   */ 
    public void addToTrie(String s);
    /**
       Returns true if the node <code>p</code> is a leaf of the trie.
       Implements 
       the function <code>IsLeaf()</code> of Section 1.3.1.
    */
    public boolean isLeaf();
  /**
     removes the string s from the trie. Implements 
       the function <code>RemoveFromTrie()</code> of Section 1.3.1.
     @param s the string to be removed
   */
    public void removeFromTrie(String s);
   /**
       Builds a trie representing the list of strings read
       from a file line by line.
       @param name the name of the file
    */
    public void fromFile(String name) throws IOException;
}