class Node<T> {
  char label;
  T value;
  Node<T> children[];

  Node(char label) {
    this.label = label;
    this.value = null;
    this.children = new Node[1<<Character.SIZE];
  }

  void set(String str, T value) {
    Node<T> cur = this;
    
    for(char c: str.toCharArray()) {
      if(cur.children[c] == null)
        cur.children[c] = new Node(c);
      cur = cur.children[c];
    }
    cur.value = value;
  }

  T get(String str) {
    Node<T> cur = this;

    for(char c: str.toCharArray()) {
      if(cur.children[c] == null)
        return null;
      cur = cur.children[c];
    }

    return cur.value;
  }

  void enumerate(String prefix) {
    prefix += label;
    if(value != null)
      System.out.println(prefix + " => " + value);
    for(int i=0; i<children.length; i++)
      if(children[i] != null)
        children[i].enumerate(prefix);
  }

  public static void main(String args[]) {
    Node<String> root = new Node((char)0);

    root.set("plop", "coucou");
    root.set("plip", "recoucou");
    root.set("abc", "zzz");
    root.set("abd", "kkk");
    System.out.println(root.get("plop"));
    root.enumerate("");
  }
}