/// Method recursive that execute the A* algorithm
  Tile? _getTileWinner(Tile current, Tile end) {
    if (end == current) return current;
    _waitList.remove(current);
    for (final element in current.neighbors) {
      if (element.parent == null) {
        _analiseDistance(element, end, parent: current);
      }
    }
    _doneList.add(current);

    for (var n in current.neighbors) {
      if (!_doneList.contains(n)) {
        _waitList.add(n);
      }
    }
    _waitList.sort((a, b) => a.f.compareTo(b.f));

    for (final element in _waitList) {
      if (!_doneList.contains(element)) {
        final result = _getTileWinner(element, end);
        if (result != null) {
          return result;
        }
      }
    }

    return null;
  }