rohacik = [ [00,10,01], [00,10,11], [10,11,01], [00,01,11] ]
stvorcek = [ [00,10,01,11] ]
hadik = [ [00,01,11,12], [01,11,10,20], [10,11,01,02], [00,10,11,21] ]
tecko = [ [01,11,10,12], [01,11,00,02], [10,11,00,20], [10,11,01,21] ]
krizik = [ [10,01,11,21,12] ]
ciarka = [ [00,01,02], [00,10,20] ]
elko = [ [00,01,11,21], [00,10,20,21], [00,10,01,02], [02,10,11,12],
    [00,10,11,12], [20,21,11,01], [00,01,02,12], [01,00,10,20] ]
$piece_shapes = [ krizik, hadik, tecko, stvorcek, elko, ciarka, rohacik ].reverse
$piece_quantities = [ 2, 2, 2, 2, 2, 2, 4 ].reverse

def empty_map()
  map = Array.new(6).map{ Array.new(10) }
  map[6] = $piece_quantities.dup
  map
end

def try_piece(map, ptype, shape, px, py)
  shape.each do |c|
    xoff = c/10; yoff = c%10
    return if px+xoff >= 10 or py+yoff >= 6 or px+xoff < 0 or py+yoff < 0
    return if map[py+yoff][px+xoff]
  end
  # past this point, the piece can be placed in there; create new entry in $solutions_to_try
  mapdup = map.collect{ |row| row.dup }
  shape.each { |c| mapdup[py+c%10][px+c/10] = ptype }
  mapdup[6][ptype] -= 1
  $solutions_to_try << mapdup
end

def find_empty_field(map)
  6.times { |y| 10.times { |x| return [x,y] if not map[y][x] } }
  nil
end

def try_solution(map)
  $timer = ($timer+1)%300; print(`clear` + dump_solution(map) + "Found: #{$progress}\n") if $timer == 0
  next_empty = find_empty_field(map)
  found_solution(map) if not next_empty
  $piece_shapes.each_with_index do |dirs,ptype|
    next if map[6][ptype] == 0
    dirs.each_with_index do |shape,pdir|
      shape.each { |c| try_piece(map, ptype, shape, next_empty[0]-c/10, next_empty[1]-c%10) }
    end
  end
end

def dump_solution(map)
  dump = []
  6.times{ |rowid| dump << map[rowid].collect{ |f| f ? (65+f).chr : "." }.join + "\n" }
  dump.join
end

def found_solution(map)
  $progress += 1
  $stderr.print "---------------\n" + dump_solution(map)
#  exit
end

$progress = 0
$timer = 0
$solutions_to_try = [ empty_map ]
while $solutions_to_try.length > 0 do try_solution($solutions_to_try.pop) end