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#!/usr/bin/env ruby
class Cart
def initialize(dir = nil)
@dir = dir
@next = :l
@moved = false
end
def moved?
@moved
end
def moved
@moved = true
end
def reset
@moved = false
end
attr_reader :dir
def turn(dir = nil)
case dir
when :l
case @dir
when :u
@dir = :l
when :d
@dir = :r
when :l
@dir = :d
when :r
@dir = :u
end
when :r
case @dir
when :u
@dir = :r
when :d
@dir = :l
when :l
@dir = :u
when :r
@dir = :d
end
else
case @next
when :l
@next = :s
self.turn(:l)
when :s
@next = :r
when :r
@next = :l
self.turn(:r)
end
end
end
end
class Cell
def initialize(track = nil, cart = nil)
@track = track
@cart = cart
end
attr_accessor :cart
attr_reader :track
def maybe_turn_cart
case @track
when :b
case @cart.dir
when :u
@cart.turn(:l)
when :d
@cart.turn(:l)
when :l
@cart.turn(:r)
when :r
@cart.turn(:r)
end
when :f
case @cart.dir
when :u
@cart.turn(:r)
when :d
@cart.turn(:r)
when :l
@cart.turn(:l)
when :r
@cart.turn(:l)
end
when :i
@cart.turn
end
end
def show
case @cart&.dir
when :u
"^"
when :d
"v"
when :l
"<"
when :r
">"
else
case @track
when :v
"|"
when :h
"-"
when :f
"/"
when :b
"\\"
when :i
"+"
else
" "
end
end
end
end
input = $stdin.readlines
grid = []
input.each do |irow|
grow = []
irow.chars.each do |cell|
case cell
when " "
grow << Cell.new
when "-"
grow << Cell.new(:h)
when "|"
grow << Cell.new(:v)
when "/"
grow << Cell.new(:f)
when "\\"
grow << Cell.new(:b)
when "+"
grow << Cell.new(:i)
when "^"
grow << Cell.new(:v, Cart.new(:u))
when "v"
grow << Cell.new(:v, Cart.new(:d))
when "<"
grow << Cell.new(:h, Cart.new(:l))
when ">"
grow << Cell.new(:h, Cart.new(:r))
end
end
grid << grow
end
loop do
carts = 0
lastcart = {x: 0, y: 0}
grid.length.times do |row|
grid[row].length.times do |col|
if grid[row][col].cart then
grid[row][col].cart.reset
lastcart[:x] = col
lastcart[:y] = row
carts += 1
end
end
end
if carts == 1 then
puts "#{lastcart[:x]},#{lastcart[:y]}"
exit 0
end
grid.length.times do |row|
grid[row].length.times do |col|
cart = grid[row][col].cart
unless cart&.moved? then
case cart&.dir
when :u
cart.moved
grid[row][col].cart = nil
newcell = grid[row-1][col]
if newcell.cart then
newcell.cart = nil
else
newcell.cart = cart
newcell.maybe_turn_cart
end
when :d
cart.moved
grid[row][col].cart = nil
newcell = grid[row+1][col]
if newcell.cart then
newcell.cart = nil
else
newcell.cart = cart
newcell.maybe_turn_cart
end
when :l
cart.moved
grid[row][col].cart = nil
newcell = grid[row][col-1]
if newcell.cart then
newcell.cart = nil
else
newcell.cart = cart
newcell.maybe_turn_cart
end
when :r
cart.moved
grid[row][col].cart = nil
newcell = grid[row][col+1]
if newcell.cart then
newcell.cart = nil
else
newcell.cart = cart
newcell.maybe_turn_cart
end
end
end
end
end
end
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