import sraja.lib.java.*;
import java.util.*;

class HTcounter {
  int nHead=0, nTail=0;

  public String toString () {
    return "[H: " + nHead + " T: " + nTail + "]";
  }
}


class Memory {
  private Hashtable store = new Hashtable ();

  char retrieve (ShiftBuffer sb) {
    String key = sb.toString();
    if (store.containsKey (key)) {
      HTcounter ht = (HTcounter) store.get(key);
      return (ht.nHead > ht.nTail ? 'h' : 't');
    } else {
      return
        (Math.random() > 0.5) ? 'h' : 't' ;
    }
  }

  void store (ShiftBuffer sb, char guess) {
    String key = sb.toString();
    if (store.containsKey (key)) {
      HTcounter ht = (HTcounter) store.get(key);
      if (guess == 'h') 
          ht.nHead++;
        else
          ht.nTail++;
    } else {
      HTcounter ht = new HTcounter ();
      if (guess == 'h') 
        ht.nHead++;
      else
        ht.nTail++;
      store.put(key,ht);
    }
  }
  
  public String toString () {
    return "Memory:\n" + store;
  }


  public static void main (String[] args) {
    Memory mem = new Memory ();
    Stdio.println (mem.toString());
    ShiftBuffer sb = new ShiftBuffer (4);
    mem.store(sb,'h');
    sb.shift('t');
    mem.store(sb,'h');
    mem.store(sb,'h');
    System.out.println (mem);
  }
}