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Tile = {}
Tile.__index = Tile
Tile.__tostring = function(self)
string = ''
for i = 1, 10 do
for j = 1, 10 do
string = string .. self:get(i, j) .. ' '
end
string = string .. "\n"
end
return string
end
function id(x, y)
return x, y
end
function Tile:new(tile)
local object = {}
object.tile = tile
object.transform = id
return setmetatable(object, self)
end
function Tile:rotate()
local old_transform = self.transform
self.transform = function(x, y)
return old_transform(y, 10 - x + 1)
end
end
function Tile:flip()
local old_transform = self.transform
self.transform = function(x, y)
return old_transform(x, 10 - y + 1)
end
end
function Tile:get(x, y)
x, y = self.transform(x, y)
return self.tile[x][y]
end
function Tile:border(horizontal, index)
first_column = 0
first_row = 0
last_column = 0
last_row = 0
if horizontal then
first_column = 1
last_column = 10
first_row = index
last_row = index
else
first_column = index
last_column = index
first_row = 1
last_row = 10
end
b = ''
for row = first_row, last_row do
for column = first_column, last_column do
b = b .. self:get(row, column)
end
end
if (horizontal and index > 1) or (not horizontal and index == 1) then
b = b:reverse()
end
return b
end
function Tile:borders()
return {
self:border(true, 1),
self:border(true, 10),
self:border(false, 1),
self:border(false, 10)
}
end
Board = {}
Board.__index = Board
function Board:new(corner)
object = {}
object.board = {}
object.board[1] = {}
object.board[1][1] = corner
return setmetatable(object, self)
end
function Board:try_add(x, y, tile)
if not self.board[x] then self.board[x] = {} end
local reference_tile = self.board[x][y - 1]
below = false
if not reference_tile then
below = true
reference_tile = self.board[x - 1][y]
end
assert(reference_tile, "tried to insert tile at non-connected location")
orientation_matches = function() return false end
if below then
orientation_matches = function()
return reference_tile:border(true, 10) == tile:border(true, 1):reverse()
end
else
orientation_matches = function()
return reference_tile:border(false, 10) == tile:border(false, 1):reverse()
end
end
correctly_rotated = false
for i = 1, 4 do
if orientation_matches() then
correctly_rotated = true
break
end
tile:rotate()
end
if not correctly_rotated then
tile:flip()
for i = 1, 4 do
if orientation_matches() then
correctly_rotated = true
break
end
tile:rotate()
end
end
if correctly_rotated then
if not self.board[x] then
self.board[x] = {}
end
self.board[x][y] = tile
end
return correctly_rotated
end
tiles = {}
current_tile_number = nil
current_tile = {}
for line in io.lines('input.txt') do
if line == "" and current_tile_number then
tiles[current_tile_number] = Tile:new(current_tile)
current_tile = {}
end
space_index = line:find(' ')
if space_index then
current_tile_number = line:sub(space_index+1, -2)
elseif #line > 0 then
row = {}
for i = 1, line:len() do
table.insert(row, line:sub(i, i))
end
table.insert(current_tile, row)
end
end
corner = '1327'
corner_tile = tiles[corner]
corner_tile:flip()
board = Board:new(tiles[corner])
handled = {}
handled[corner] = true
visited = {}
visited[1] = {}
visited[1][1] = true
visited[2] = {}
visited[2][1] = true
visited[1][2] = true
queue = {}
table.insert(queue, {1, 2})
table.insert(queue, {2, 1})
while #queue ~= 0 do
current = table.remove(queue, 1)
x = current[1]
y = current[2]
inserted = false
for tile_id, tile in pairs(tiles) do
if not handled[tile_id] then
if board:try_add(x, y, tile) then
assert(board.board[x][y])
inserted = true
handled[tile_id] = true
if not visited[x] then visited[x] = {} end
if not visited[x + 1] then visited[x + 1] = {} end
if x < 12 and not visited[x + 1][y] then
table.insert(queue, {x + 1, y})
visited[x + 1][y] = true
end
if y < 12 and not visited[x][y + 1] then
table.insert(queue, {x, y + 1})
visited[x][y + 1] = true
end
break
end
end
end
if not inserted then
print('failed')
break
end
end
for i = 1, 12 do
for x = 2, 9 do
for j = 1, 12 do
local tile = board.board[i][j]
for y = 2, 9 do
io.write(tile:get(x, y))
end
end
print()
end
end
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