RosettaCodeData/Task/Maze-generation/Phix/maze-generation.phix
2017-09-25 22:28:19 +02:00

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--
-- grid is eg for w=3,h=2: {"+---+---+---+", -- ("wall")
-- "| ? | ? | ? |", -- ("cell")
-- "+---+---+---+", -- ("wall")
-- "| ? | ? | ? |", -- ("cell")
-- "+---+---+---+", -- ("wall")
-- ""} -- (for a trailing \n)
--
-- note those ?(x,y) are at [y*2][x*4-1], and we navigate
-- using y=2..2*h (+/-2), x=3..w*4-1 (+/-4) directly.
--
constant w = 11, h = 8
sequence wall = join(repeat("+",w+1),"---")&"\n",
cell = join(repeat("|",w+1)," ? ")&"\n",
grid = split(join(repeat(wall,h+1),cell),'\n')
procedure amaze(integer x, integer y)
grid[y][x] = ' ' -- mark cell visited
sequence p = shuffle({{x-4,y},{x,y+2},{x+4,y},{x,y-2}})
for i=1 to length(p) do
integer {nx,ny} = p[i]
if nx>1 and nx<w*4 and ny>1 and ny<=2*h and grid[ny][nx]='?' then
integer mx = (x+nx)/2
grid[(y+ny)/2][mx-1..mx+1] = ' ' -- knock down wall
amaze(nx,ny)
end if
end for
end procedure
function heads()
return rand(2)=1 -- 50:50 true(1)/false(0)
end function
integer {x,y} = {(rand(w)*4)-1,rand(h)*2}
amaze(x,y)
-- mark start pos
grid[y][x] = '*'
-- add a random door (heads=rhs/lhs, tails=top/btm)
if heads() then
grid[rand(h)*2][heads()*w*4-1] = ' '
else
x = rand(w)*4-1
grid[heads()*h*2+1][x-1..x+1] = ' '
end if
puts(1,join(grid,'\n'))