#/***********************************************************
#    maze.rb -- 迷路
#***********************************************************/
XMAX = 80
YMAX = 24
MAXSITE = (XMAX * YMAX / 4)  # 最大サイト数 
row = Array.new(YMAX+1).fill(0)
map = []; (XMAX+1).times { map.push(row.dup) }
$nsite = 0
$xx = []
$yy = []
$dx = [2, 0, -2,  0]
$dy = [0, 2,  0, -2]

dirtable = [
    [0,1,2,3], [0,1,3,2], [0,2,1,3], [0,2,3,1], [0,3,1,2], [0,3,2,1],
    [1,0,2,3], [1,0,3,2], [1,2,0,3], [1,2,3,0], [1,3,0,2], [1,3,2,0],
    [2,0,1,3], [2,0,3,1], [2,1,0,3], [2,1,3,0], [2,3,0,1], [2,3,1,0],
    [3,0,1,2], [3,0,2,1], [3,1,0,2], [3,1,2,0], [3,2,0,1], [3,2,1,0]
    ]

def add(i, j)  # サイトに加える 
    $xx[$nsite] = i;  $yy[$nsite] = j;  $nsite += 1
end

def select  # サイトを乱数で選ぶ 
    if ($nsite == 0); return 0, 0, 0; end   # サイトが尽きた 
    $nsite -= 1;  r = ($nsite * rand()).to_i
    i = $xx[r];  $xx[r] = $xx[$nsite]
    j = $yy[r];  $yy[r] = $yy[$nsite]
    return 1, i, j                          # 成功 
end

srand(Time.new.to_i);  # 時刻で乱数を初期化 
for i in 0..XMAX
    for j in 0..YMAX; map[i][j] = 1; end
end
for i in 3..(XMAX-3)
    for j in 3..(YMAX-3); map[i][j] = 0; end
end
map[2][3] = 0;  map[XMAX - 2][YMAX - 3] = 0
4.step(XMAX-4, 2) do |i|
    add(i, 2);  add(i, YMAX - 2)
end
4.step((YMAX - 4),  2) do |j|
    add(2, j);  add(XMAX - 2, j)
end
while (((flag, i, j = select()) != []) && flag == 1)   # サイトを選ぶ 
    while (true)          # そこから延ばしていく 
        tt = dirtable[(24 * rand()).to_i]
        d = 3; while(d >= 0)
            t = tt[d];  i1 = i + $dx[t];  j1 = j + $dy[t]
            if (map[i1][j1] == 0); break; end
            d -= 1
        end
        if (d < 0); break; end
        map[(i + i1) / 2][(j + j1) / 2] = 1
        i = i1;  j = j1;  map[i][j] = 1;  add(i, j)
    end
end
for j in 2..(YMAX-2)
    for i in 2..(XMAX-2)
        if (map[i][j] == 1); putc(?X); else; putc(?\s); end
    end
    putc(?\n)
end

exit 0