Android Open Source - iSlide Game Board

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Back to project page iSlide.

License

The source code is released under:

MIT License

Java Source Code

package edu.csun.group2.islide.engine;
/*from  w  ww.j a v a 2s.  c om*/
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
//import java.util.ArrayList;


public class GameBoard extends Board {
  
  public ArrayDeque<Pair> solution_stack;  
  private HashMap<Integer, Board> hash;
  private int solution_code;

  public GameBoard(int size) {
    super(size);
    solution_code = this.ary.hashCode();
    Random rand = new Random();
    rand.setSeed(rand.nextInt(1000));// need to seed the number generator to make it deterministic.
    int solution_length;
    if (size <= 5) {
      solution_length = rand.nextInt(2 * (size * size))
          + ((6 * size) + 64);
    }
    else{
      solution_length =  rand.nextInt(500) + 300 + (size*size);
    }
    hash = new HashMap<Integer, Board>(solution_length);
    solution_stack = new ArrayDeque<Pair>(solution_length);
    
    
    // make a copy of the solution board 
    // making a new board an initializing it is expensive, this copy is much cheaper
    Board board = new Board(this);
    
    ArrayList<Pair> temp;
    Pair p;
    // until the # of moves is full
    while(solution_stack.size() < solution_length)
    {
              
      temp = adjacent_moves(board);
      // if there were no valid moves, go back and look for more valid moves (backtrack)
      while(temp.isEmpty())
      {
        solution_stack.pop();          
        temp = adjacent_moves(solution_stack.peek().board);
      }
      
      p = temp.get(rand.nextInt(temp.size()));// pick a random move
      board = p.board;      
      
      hash.put(board.hashCode(), board);// add the new move to the hash
      solution_stack.push(p);      
    }
    
    
    // our actual board is in the solution state, 
    // so replay the move list we just made in proper order
    ArrayDeque<Pair> s = solution_stack.clone();
    solution_stack.clear();
    while(!s.isEmpty())    
      this.move(s.pollLast().index);
    
    
  }

  @SuppressWarnings("unchecked")
  public GameBoard(GameBoard other) {
    super(other);
    solution_stack = other.solution_stack.clone();
    hash = (HashMap<Integer, Board>) other.hash.clone();    
  }
  
  
  /**
   * 
   * @param board
   * @return The list of moves not yet seen;
   */
  private ArrayList<Pair> adjacent_moves(Board board)
  {
    
    ArrayList<Pair> ret = new ArrayList<Pair>(4); 
    int empty = board.empty;    
    int index;
    {
      Board temp = new Board(board);
      index = empty +1;
      if(temp.move(index) && !hash.containsKey(temp.hashCode()))
        ret.add(new Pair(empty, temp));      
    }
    
    {
      Board temp = new Board(board);
      index = empty - 1;
      if(temp.move(index) && !hash.containsKey(temp.hashCode()))
        ret.add(new Pair(empty, temp));
    }
    
    {
      Board temp = new Board(board);
      index = empty + temp.width;
      if(temp.move(index) && !hash.containsKey(temp.hashCode()))
        ret.add(new Pair(empty, temp));
    }
    
    {
      Board temp = new Board(board);
      index = empty - temp.width;
      if(temp.move(index) && !hash.containsKey(temp.hashCode()))
        ret.add(new Pair(empty, temp));
    }
    
    return ret;
    
  }

  public boolean move(int index)
  {
    int e = empty;
    if(super.move(index))// if the move was successful
    {
      Board b = new Board(this);
      Pair p = new Pair(e, b);// make a new pair to put in the stack
      // if the move is already in the solution, get rid of don't add it, 
      // and get rid of extra moves
      if(solution_stack.contains(p))
      {
        while(solution_stack.peek() != null && !solution_stack.peek().Equals(p))
          solution_stack.pop();        
      }
      else
        solution_stack.push(p);
      return true;
    }    
    return false;    
  }
  
  /**
   * 
   * @return the index of the next move in the solution
   */
  public int hint()
  {
    return solution_stack.peek().index;
  }
  
  public int solve()
  {
    Pair p = solution_stack.pop();
    super.move(p.index);
    return p.index;
  }
  
  public boolean solved()
  {
    return this.ary.hashCode() == solution_code;
  }
  
  
  
}

Java Source Code List

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