From: Martin Boese <boesemar@...>
Date: 2009-03-17T02:04:13+09:00
Subject: Re: [QUIZ] Sliding Puzzle (#196)

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My small solution attached. It will create an 8-puzzle by default, but
can do n-puzzle if you specify width and height as parameters.

Then you can shuffle it with 's' key - it will make 100 random moves.

Everything else remains basic... so the party when solved ;-)

Martin


On Sat, 2009-03-14 at 00:49 +0900, Daniel Moore wrote:
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> 
> The three rules of Ruby Quiz:
> 
> 1.  Please do not post any solutions or spoiler discussion for this
> quiz until 48 hours have elapsed from the time this message was
> sent.
> 
> 2.  Support Ruby Quiz by submitting ideas and responses
> as often as you can! Visit: <http://rubyquiz.strd6.com>
> 
> 3.  Enjoy!
> 
> Suggestion:  A [QUIZ] in the subject of emails about the problem
> helps everyone on Ruby Talk follow the discussion.  Please reply to
> the original quiz message, if you can.
> 
> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> 
> ## Sliding Puzzle (#196)
> 
> Bienvenidos fellow Rubyists,
> 
> This weeks quiz will be to create and implement a [sliding puzzle][1].
> The puzzle must be playable from keyboard input. The program will
> generate a puzzle in a random configuration and the puzzle generated
> must be solvable. You may create either the 8-puzzle or the 15-puzzle.
> You may include a mode that will automatically solve the puzzle or
> present a hint.
> 
> The puzzle must throw a small party when solved.
> 
> Bonus: Have the puzzle be displayed as an ascii art image that needs
> to be arranged instead of simple numbers.
> 
> [1]: http://en.wikipedia.org/wiki/Fifteen_puzzle
> 
> 
> Have Fun!

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class Puzzle
 def initialize(x,y)
   @board = mkboard(x,y)
   @x, @y = x, y
 end

 def mkboard(x,y)
   board = Array.new(x*y) { |e| e+1 }
   board[-1] = nil
   board
 end

 def put(x,y,c)
   @board[y*@y+x] = c
 end
 
 def get(x,y)
   @board[y*@y+x]
 end

 # index -> coordinates
 def i2c(idx)
   [(idx % @y), (idx / @y)]
 end

 def dump
   (0..(@y-1)).to_a.each { |y| (0..(@x-1)).to_a.each { |x| $stdout.print get(x,y) ? "%3d" % get(x,y) : '   '  }; puts }
 end
 
 def solved? 
   @board == mkboard(@x,@y) && @moved 
 end

 def move(direction)
   x,y = i2c(@board.index(nil))
   fx, fy = x,y

   case direction
      when 'u'
       fy = y+1
     when 'd'
       fy = y-1
     when 'l'
       fx = x+1
     when 'r'
       fx = x-1
   end

   return if ((fx >= @x) || (fx < 0) || (fy >= @y) || (fy < 0))
   return if ((fx == x) && (fy == y))
 
   @moved = true
   
   put(x,y, get(fx,fy))
   put(fx,fy,nil)
 end
 
 def shuffle
   100.times { move 'udlr'[(rand*4).to_i].chr }
 end
end

p = Puzzle.new((ARGV[0] || 3).to_i,(ARGV[1] || 3).to_i)

while (!p.solved?) do
 p.dump
 print "Use (U)p, (D)own, (L)eft, (R)ight, (S)huffle, (Q)uit: "
 command = $stdin.gets[0].chr.downcase
 
 p.shuffle if command == 's'
 exit if command == 'q' 
 p.move command
end

puts
10.times { $stdout.print '*'; sleep 0.1; $stdout.flush } 
puts " You won!\n"

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