Question

我目前正在尝试制作蛇寻路算法。我试图做点什么，但是我发现问题很难找到。问题是我以递归方式实现算法，该方法没有找到一条路径，但是由于控制台窗口大，所以可以搜索导致堆栈溢出异常的所有可用路径。

“网格”是一个二维布尔数组，与控制台一样大，如果在控制台上有类似蛇的部分，则值为true。 / em>

方向 是一个包含Up，Down，Left，Right值的枚举。位置是一个带有两个整数的结构，称为X和Y。

ScheduledDirections 是一个列表，其中包含将来用于蛇在控制台上绘图的路线。

我想要做的是快速添加一个可用路径到该列表。我知道像A *这样的寻路算法，但我发现它太复杂而且难以实现。

这是我用来查找可用路径的方法：

private static void FindAvailablePath(Position currentPosition, Direction currentDirection) { // break if the snake's path search has ended or it went out of the console if (currentPosition.X < 0 || currentPosition.X >= Console.WindowWidth || currentPosition.Y < 0 || currentPosition.Y >= Console.WindowHeight || AIController.isReady) { return; } // break if there is something that is blocking the snake's path if (Snake.Grid[currentPosition.X, currentPosition.Y]) { return; } // break if the snake has reached its destination if (currentPosition.Equals(AIController.Destination)) { AIController.isReady = true; return; } // if the current path is available, adds it to the collection and checks for the next one if (!Snake.Grid[currentPosition.X, currentPosition.Y]) { AIController.scheduledDirections.Add(currentDirection); FindAvailablePath(new Position(currentPosition.X + 1, currentPosition.Y), Direction.Right); // right FindAvailablePath(new Position(currentPosition.X, currentPosition.Y - 1), Direction.Up); // up FindAvailablePath(new Position(currentPosition.X - 1, currentPosition.Y), Direction.Left); // left FindAvailablePath(new Position(currentPosition.X, currentPosition.Y + 1), Direction.Down); // down } }

如果某人有更好的想法，我会很高兴听到他们。谢谢！

Answer 1

你必须确保蛇不会回到已经“访问过”的位置，否则你的代码将不得不探索无限多种可能性（在相同的四个方格中圈出一次，两次，三次，......，四十亿次等。）。

这意味着您必须记录所访问的职位并检查该职位。

这应该可以解决问题：

private static void FindAvailablePath(Position currentPosition, Stack<Position> previousPositions, Direction currentDirection, Stack<Drection> previousDirections)
{
    // break if the snake's path search has ended or it went out of the console
    if (currentPosition.X < 0 || currentPosition.X >= Console.WindowWidth ||
        currentPosition.Y < 0 || currentPosition.Y >= Console.WindowHeight)
    {
        return;
    }

    // break if there is something that is blocking the snake's path
    if (Snake.Grid[currentPosition.X, currentPosition.Y])
    {
        return;
    }

    // break if the snake has reached its destination
    if (currentPosition.Equals(AIController.Destination))
    {
        if(AIController.scheduledDirections == null || AIController.scheduledDirections.Count > previousDirections.Count + 1)
        {
            AIController.scheduledDirections = previousDirections.ToList();
            AIController.scheduledDirections.Add(currentDirection);
        }
        return;
    }

    // Break if previously visited
    if(previousPositions.Contains(currentPosition))
    {
        return;
    }


    // if the current path is available, adds it to the collection and checks for the next one
    previousPositions.Push(currentPosition);
    previousDirections.Push(currentDirection);

    FindAvailablePath(new Position(currentPosition.X + 1, currentPosition.Y), previousPositions, Direction.Right, previousDirections); // right
    FindAvailablePath(new Position(currentPosition.X, currentPosition.Y - 1), previousPositions, Direction.Up, previousDirections);    // up
    FindAvailablePath(new Position(currentPosition.X - 1, currentPosition.Y), previousPositions, Direction.Left, previousDirections);  // left
    FindAvailablePath(new Position(currentPosition.X, currentPosition.Y + 1), previousPositions, Direction.Down, previousDirections);  // down

    previousPositions.Pop();
    previousDirections.Pop();
}

此外，专业提示：向您的位置结构添加“左”，“右”，“顶部”，“向下”方法，这些方法返回正确方向的新位置。这使您的代码更具可读性。

Snake寻路算法异常

1 个答案: