Greedy Algorithm for 2048

gistfile1.js

/**
 * Copy paste in the console, then restart the game (space bar)
 *
 * Greedy Algorithm for : http://gabrielecirulli.github.io/2048/
 * Plays the game using a naive greedy method. i.e. Local maximum
 *
 * Azaan
 */
(function () {
  var __restart = GameManager.prototype.restart;
  var GM;

  GameManager.prototype.restart = function () {
    GM = this;
    __restart.bind(this)();

    var strategy = new GreedyStrategy(GM);
    console.log('hi');
    setTimeout(function () {
      strategy.play(window.DELAY || 100);
    }, 0);
  };

  function GreedyStrategy(gm) {
    this.gm = gm;
  }

  GreedyStrategy.prototype.cloneGrid = function () {
    function cloneTile(tile) {
      var t = new Tile({x: tile.x, y: tile.y}, tile.value);
      t.previousPosition = tile.previousPosition;
      t.mergedFrom = tile.mergedFrom;
      return t;
    }

    var arr = [], i, j, len, len2;
    for (i = 0, len = this.gm.grid.size; i < len; i++) {
      arr[i] = this.gm.grid.cells[i].slice();

      for (j = 0, len2 = arr[i].length; j < len2; j++) {
        if (arr[i][j] !== null) {
          arr[i][j] = cloneTile(arr[i][j]);
        }
      }
    }

    var g = new Grid(this.gm.grid.size);
    g.cells = arr;
    return g;
  };

  GreedyStrategy.prototype.freeze = function () {
    this._grid = this.gm.grid;
    this._act = this.gm.actuator;
    this._score = this.gm.score;
    this._over = this.gm.over;
    this._won = this.gm.won;

    this.gm.actuator = undefined;
    this.gm.grid = this.cloneGrid();
  };

  GreedyStrategy.prototype.restore = function () {
    this.gm.grid = this._grid;
    this.gm.actuator = this._act;
    this.gm.score = this._score;
    this.gm.won = this._won;
    this.gm.over = this._over;
  };

  GreedyStrategy.prototype.step = function () {
    var scores = [], i;

    for (i = 0; i < 4; i++) {
      this.freeze();

      try {
        this.gm.move(i);
        scores.push(-Infinity);
      } catch (e) {
        // add score only if something moved
        scores.push(this.gm.score);
      }


      this.restore();
    }

    return scores;
  };

  GreedyStrategy.prototype.play = function (d) {
    var self = this, next;
    var delay = d || 0;

    next = function () {
      var maxI = 0, scores;

      scores = self.step();
      for (i = 0; i < 4; i++) {
        if (scores[i] > scores[0])
          maxI = i;
      }

      console.log(scores);
      window.requestAnimationFrame(function () {
        self.gm.move(maxI);

        if (!self.gm.over) {
          setTimeout(next, delay);
        }
      });
    };

    next();
  };

  new GameManager(4, KeyboardInputManager, HTMLActuator);
})();