【C#】壁伸ばし法で迷路を生成する

迷路の幅と高さをそれぞれ width, height として設定し、
その数値にしたがって壁伸ばし法で迷路を生成する。
※迷路の幅と高さは5以上の奇数とする。

using System;
using System.Collections.Generic;
using System.Linq;

public class Maze {
    public const int PATH = 0;
    public const int WALL = 1;
    public int width;
    public int height;
    public int[,] maze;
    public int[] start;
    private Random random;
    
    public Maze(int width, int height, int seed = 0) {
        this.width = width;
        this.height = height;
        if (this.width < 5 || this.height < 5) {
            Environment.Exit(0);
        }
        if (this.width % 2 == 0) {
            this.width++;
        }
        if (this.height % 2 == 0) {
            this.height++;
        }
        this.maze = new int[this.height,this.width];
        for (int y = 0; y < this.height; ++y) {
            for (int x = 0; x < this.width; ++x) {
                this.maze[y,x] = Maze.PATH;
            }
        }
        this.start = new int[] {1, 1};
        this.random = new Random(seed);
    }

    public int[,] set_outer_wall() {
        for (int y = 0; y < this.height; ++y) {
            for (int x = 0; x < this.width; ++x) {
                if (x == 0 || y == 0 || x == this.width-1 || y == this.height-1) {
                    this.maze[y,x] = Maze.WALL;
                }
            }
        }
        return this.maze;
    }

    public int[,] set_maze_kabenobashi() {
        this.set_outer_wall();
        int[] point;
        Stack<int[]> stack = new Stack<int[]>();
        for (int y = 2; y < this.height-1; y += 2) {
            for (int x = 2; x < this.width-1; x += 2) {
                stack.Push(new int[] {x, y});
            }
        }
        while (true) {
            if (stack.Count == 0) {
                break;
            }
            stack = new Stack<int[]>(stack.OrderBy(i => random.Next(stack.Count)).ToArray());
            point = stack.Pop();
            if (this.maze[point[1],point[0]] == Maze.WALL) {
                continue;
            }
            this.maze[point[1],point[0]] = Maze.WALL;
            List<int[]> extend_wall = new List<int[]>();
            extend_wall.Add(new int[] {point[0],point[1]});
            while (true) {
                List<int> directions = new List<int>();
                CellComparer comparer  = new CellComparer();
                if (this.maze[point[1]-1,point[0]] == Maze.PATH && extend_wall.Contains(new int[] {point[0],point[1]-2}, comparer) != true) {
                    directions.Add(0);
                }
                if (this.maze[point[1],point[0]+1] == Maze.PATH && extend_wall.Contains(new int[] {point[0]+2,point[1]}, comparer) != true) {
                    directions.Add(1);
                }
                if (this.maze[point[1]+1,point[0]] == Maze.PATH && extend_wall.Contains(new int[] {point[0],point[1]+2}, comparer) != true) {
                    directions.Add(2);
                }
                if (this.maze[point[1],point[0]-1] == Maze.PATH && extend_wall.Contains(new int[] {point[0]-2,point[1]}, comparer) != true) {
                    directions.Add(3);
                }
                if (directions.Count == 0) {
                    break;
                }
                int direction = directions[random.Next(directions.Count)];
                switch (direction) {
                    case 0:
                        if (this.maze[point[1]-2,point[0]] == Maze.WALL) {
                            this.maze[point[1]-1,point[0]] = Maze.WALL;
                            goto LOOPEND;
                        } else {
                            this.maze[point[1]-1,point[0]] = Maze.WALL;
                            this.maze[point[1]-2,point[0]] = Maze.WALL;
                            extend_wall.Add(new int[] {point[0],point[1]-2});
                            point = new int[] {point[0],point[1]-2};
                            break;
                        }
                    case 1:
                        if (this.maze[point[1],point[0]+2] == Maze.WALL) {
                            this.maze[point[1],point[0]+1] = Maze.WALL;
                            goto LOOPEND;
                        } else {
                            this.maze[point[1],point[0]+1] = Maze.WALL;
                            this.maze[point[1],point[0]+2] = Maze.WALL;
                            extend_wall.Add(new int[] {point[0]+2,point[1]});
                            point = new int[] {point[0]+2,point[1]};
                            break;
                        }
                    case 2:
                        if (this.maze[point[1]+2,point[0]] == Maze.WALL) {
                            this.maze[point[1]+1,point[0]] = Maze.WALL;
                            goto LOOPEND;
                        } else {
                            this.maze[point[1]+1,point[0]] = Maze.WALL;
                            this.maze[point[1]+2,point[0]] = Maze.WALL;
                            extend_wall.Add(new int[] {point[0],point[1]+2});
                            point = new int[] {point[0],point[1]+2};
                            break;
                        }
                    case 3:
                        if (this.maze[point[1],point[0]-2] == Maze.WALL) {
                            this.maze[point[1],point[0]-1] = Maze.WALL;
                            goto LOOPEND;
                        } else {
                            this.maze[point[1],point[0]-1] = Maze.WALL;
                            this.maze[point[1],point[0]-2] = Maze.WALL;
                            extend_wall.Add(new int[] {point[0]-2,point[1]});
                            point = new int[] {point[0]-2,point[1]};
                            break;
                    }
                }
            }
            LOOPEND:;
        }
        return this.maze;
    }

    public void print_maze() {
        for (int y = 0; y < this.maze.GetLength(0); ++y) {
            for (int x = 0; x < this.maze.GetLength(1); ++x) {
                if (this.maze[y,x] == Maze.WALL) {
                    Console.Write('#');
                } else if (this.maze[y,x] == Maze.PATH) {
                    Console.Write(' ');
                }
            }
            Console.WriteLine();
        }
    }
    
    private class CellComparer : IEqualityComparer<int[]>
    {
        public bool Equals(int[] x, int[] y)
        {
            if(x[0] == y[0] && x[1] == y[1]) {
                return true;
            } else {
                return false;
            }
        }
        public int GetHashCode(int[] x)
        {
            return 0;
        }
    }

    public static void Main() {
        Maze maze1 = new Maze(15, 15);
        maze1.set_maze_kabenobashi();
        maze1.print_maze();
    }
}

今回は、以下のように出力される。

###############
#     #   # # #
# ### # ### # #
# # # # #     #
# # ### # #####
#             #
# # ### # # # #
# #   # # # # #
##### ##### ###
#     # #     #
# ##### # # # #
# #       # # #
# ##### # ### #
#     # # #   #
###############