RosettaCodeData/Task/Maze-generation/C-sharp/maze-generation.cs
2023-07-01 13:44:08 -04:00

124 lines
3.8 KiB
C#

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Drawing;
namespace MazeGeneration
{
public static class Extensions
{
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source, Random rng)
{
var e = source.ToArray();
for (var i = e.Length - 1; i >= 0; i--)
{
var swapIndex = rng.Next(i + 1);
yield return e[swapIndex];
e[swapIndex] = e[i];
}
}
public static CellState OppositeWall(this CellState orig)
{
return (CellState)(((int) orig >> 2) | ((int) orig << 2)) & CellState.Initial;
}
public static bool HasFlag(this CellState cs,CellState flag)
{
return ((int)cs & (int)flag) != 0;
}
}
[Flags]
public enum CellState
{
Top = 1,
Right = 2,
Bottom = 4,
Left = 8,
Visited = 128,
Initial = Top | Right | Bottom | Left,
}
public struct RemoveWallAction
{
public Point Neighbour;
public CellState Wall;
}
public class Maze
{
private readonly CellState[,] _cells;
private readonly int _width;
private readonly int _height;
private readonly Random _rng;
public Maze(int width, int height)
{
_width = width;
_height = height;
_cells = new CellState[width, height];
for(var x=0; x<width; x++)
for(var y=0; y<height; y++)
_cells[x, y] = CellState.Initial;
_rng = new Random();
VisitCell(_rng.Next(width), _rng.Next(height));
}
public CellState this[int x, int y]
{
get { return _cells[x,y]; }
set { _cells[x,y] = value; }
}
public IEnumerable<RemoveWallAction> GetNeighbours(Point p)
{
if (p.X > 0) yield return new RemoveWallAction {Neighbour = new Point(p.X - 1, p.Y), Wall = CellState.Left};
if (p.Y > 0) yield return new RemoveWallAction {Neighbour = new Point(p.X, p.Y - 1), Wall = CellState.Top};
if (p.X < _width-1) yield return new RemoveWallAction {Neighbour = new Point(p.X + 1, p.Y), Wall = CellState.Right};
if (p.Y < _height-1) yield return new RemoveWallAction {Neighbour = new Point(p.X, p.Y + 1), Wall = CellState.Bottom};
}
public void VisitCell(int x, int y)
{
this[x,y] |= CellState.Visited;
foreach (var p in GetNeighbours(new Point(x, y)).Shuffle(_rng).Where(z => !(this[z.Neighbour.X, z.Neighbour.Y].HasFlag(CellState.Visited))))
{
this[x, y] -= p.Wall;
this[p.Neighbour.X, p.Neighbour.Y] -= p.Wall.OppositeWall();
VisitCell(p.Neighbour.X, p.Neighbour.Y);
}
}
public void Display()
{
var firstLine = string.Empty;
for (var y = 0; y < _height; y++)
{
var sbTop = new StringBuilder();
var sbMid = new StringBuilder();
for (var x = 0; x < _width; x++)
{
sbTop.Append(this[x, y].HasFlag(CellState.Top) ? "+---" : "+ ");
sbMid.Append(this[x, y].HasFlag(CellState.Left) ? "| " : " ");
}
if (firstLine == string.Empty)
firstLine = " " + sbTop.ToString();
Debug.WriteLine(" " + sbTop + "+");
Debug.WriteLine(" " + sbMid + "|");
}
Debug.WriteLine(firstLine);
}
}
class Program
{
static void Main(string[] args)
{
var maze = new Maze(20, 20);
maze.Display();
}
}
}