path: root/22/2.lua

require "ext"
local parse_map = true
local map = {}
local row,col = 0,0
	local start
	local commands = {}

	local function parse_command(line)
		local commands = {}
		local ccursor = line
		while ccursor ~= "" do
		if ccursor:find("^%d") then
			table.insert(commands,{type="walk",n=ccursor:match("^(%d+)")})
			ccursor = ccursor:gsub("^(%d+)","")
		elseif ccursor:find("^[LR]") then
			table.insert(commands,{type="turn",n=ccursor:match("^([LR])")})
			ccursor = ccursor:gsub("^[LR]","")
		end
	end
	return commands
end

for line in io.lines() do
	row = row + 1
	if line ~= "" and parse_map then
		col = 0
		for char in line:gmatch("(.)") do
			col = col + 1
			local locf = string.format("%d,%d",row,col)
			if char == "." then
				if start == nil then
					start = locf
				end
				map[locf] = true
			elseif char == "#" then
				map[locf] = false
			end --else, it's nil
		end
	elseif line == "" and parse_map then
		parse_map = false
	elseif not parse_map then
		commands = parse_command(line)
	end
end

local directions = {
	up = {-1, 0},
	down = {1,0},
	left = {0,-1},
	right = {0,1}
}
local dirmap = {
	[0] = {
		name = "right",
		R = 1,
		L = 3
	},
	[1] = {
		name = "down",
		R = 2,
		L = 0
	},
	[2] = {
		name = "left",
		R = 3,
		L = 1
	},
	[3] = {
		name = "up",
		R = 0,
		L = 2
	}
}
local dirnames = {
	[directions.up] = "up",
	[directions.down] = "down",
	[directions.left] = "left",
	[directions.right] = "right"
}
local rev_dirmap = {}
for i,t in pairs(dirmap) do
	rev_dirmap[t.name] = i
end


local mem_loop = {}
--Planning:
-- 6 <-> 7
-- 5 <-> 9
-- 13 <-> 12
--
-- 1 <-> 11
-- 2 <-> 14
-- 4 <-> 10
-- 8 <-> 3
local function find_loop_loc(sloc, direction)
	print("Finding loop location from",sloc,"dir",dirnames[direction])
	--[[
	if mem_loop[sloc] and mem_loop[sloc][direction] then
		return mem_loop[sloc][direction][1], mem_loop[sloc][direction][2]
	end
	]]
	local srow, scol = sloc:match("(%d+),(%d+)")
	srow, scol = tonumber(srow),tonumber(scol)
	--just hard-code looping rules
	local rloc, rdir
	if srow == 1 and scol > 50 and scol <= 100 and direction == directions.up then -- 1 -> 11
		print("1->11")
		rloc = string.format("%d,%d",100+scol,1)
		rdir = rev_dirmap.right
	elseif scol == 1 and srow > 150 and srow <= 200 and direction == directions.left then -- 11 -> 1
		print("11->1")
		rloc = string.format("%d,%d",1,srow - 100)
		rdir = rev_dirmap.down
	elseif srow == 1 and scol > 100 and scol <= 150 and direction == directions.up then -- 2 -> 14
		print("2->14")
		rloc = string.format("%d,%d", 200, scol - 100)
		rdir = rev_dirmap.up
	elseif srow == 200 and scol > 0 and scol <= 50 and direction == directions.down then -- 14 ->2 
		print("14->2")
		rloc = string.format("%d,%d", 1, scol + 100)
		rdir = rev_dirmap.down
	elseif scol == 51 and srow > 0 and srow <= 50 and direction == directions.left then -- 3 -> 8
		print("3->8")
		rloc = string.format("%d,%d", (50 - srow) + 101, 1)
		rdir = rev_dirmap.right
	elseif scol == 1 and srow > 100 and srow <= 150 and direction == directions.left then -- 8 -> 3
		print("8->3")
		rloc = string.format("%d,%d", ((150 - srow) - 100) + 101, 51)
		rdir = rev_dirmap.right
	elseif scol == 150 and srow > 0 and srow <= 100 and direction == directions.right then -- 4 -> 10
		print("4->10")
		rloc = string.format("%d,%d", (50 - srow) + 101, 100)
		rdir = rev_dirmap.left
	elseif scol == 100 and srow > 100 and srow <= 150 and direction == directions.right then -- 10 -> 4
		print("10->4")
		rloc = string.format("%d,%d", (151 - srow), 150)
		rdir = rev_dirmap.left
	elseif scol == 51 and srow > 50 and srow <= 100 and direction == directions.left then -- 5 -> 9
		print("5->9")
		rloc = string.format("%d,%d", 101, srow-50)
		rdir = rev_dirmap.down
	elseif srow == 101 and scol > 0 and scol <= 50 and direction == directions.up then -- 9 -> 5
		print("9->5")
		rloc = string.format("%d,%d", scol + 50, 51)
		rdir = rev_dirmap.right
	elseif srow == 50 and scol > 100 and scol <= 150 and direction == directions.down then -- 6 -> 7
		print("6->7")
		rloc = string.format("%d,%d", scol - 50, 100)
		rdir = rev_dirmap.left
	elseif scol == 100 and srow > 50 and srow <= 100 and direction == directions.right then -- 7 -> 6
		print("7->6")
		rloc = string.format("%d,%d", 50, srow + 50)
		rdir = rev_dirmap.up
	elseif srow == 150 and scol > 50 and scol <= 100 and direction == directions.down then -- 12 -> 13
		print("12->13")
		rloc = string.format("%d,%d", scol + 100, 50)
		rdir = rev_dirmap.left
	elseif scol == 50 and srow > 150 and srow <= 200 and direction == directions.right then -- 13 -> 12
		print("13->12")
		rloc = string.format("%d,%d", 150, srow - 100)
		rdir = rev_dirmap.up
	else
		error(string.format("Unknown location + direction: %d,%d %s",srow, scol, tostring(direction)))
	end
	print("Returning",rloc,rdir)
	assert(rloc)
	assert(rdir)
	assert(map[rloc] ~= nil)

	mem_loop[rloc] = mem_loop[rloc] or {}
	mem_loop[rloc][direction] = {rloc,rdir}
	return rloc, rdir
end

print(map)
local state = {
	location = start,
	direction = 0
}
print("Starting state:",state)

local function open(location,direction)
	local crow, ccol = location:match("(%d+),(%d+)")
	local rrow, rcol = crow + direction[1], ccol + direction[2]
	local rloc = string.format("%d,%d",rrow,rcol)
	if map[rloc] then
		return rloc, rev_dirmap[dirnames[direction]]
	elseif map[rloc] == false then
		return false
	else
		local loop_loc,newdir = find_loop_loc(location,direction)
		assert(map[loop_loc] ~= nil)
		if map[loop_loc] then
			return loop_loc,newdir
		else
			return false
		end
	end
end

-- temporary function to test our cube is put togeather correctly
local function exists(location,direction)
	assert(type(location) == "string")
	assert(type(direction) == "table")
	print("Exists",location,dirnames[direction])
	local crow, ccol = location:match("(%d+),(%d+)")
	local rrow, rcol = crow + direction[1], ccol + direction[2]
	local rloc = string.format("%d,%d",rrow,rcol)
	print("checking existance of",rloc)
	if map[rloc] ~= nil then
		print("Exists in map")
		return rloc,rev_dirmap[dirnames[direction]]
	else
		print("Looping around")
		local loop_loc,newdir = find_loop_loc(location,direction)
		assert(map[loop_loc] ~= nil)
		assert(type(newdir) == "number")
		return loop_loc,newdir
	end

end

local corners = {
	{1,51, directions.up},
	{1,100, directions.right},
	{50,51},
	{50,100},
	{50,101},
	{51,51},
	{51,100},
	{101,1},
	{101,50},
	{101,51},
	{101,100},
	{150,1},
	{150,50},
	{150,51},
	{150,100},
	{200,1},
	{200,50}
}
local edges = {

}

--[[
-- test find_loop_loc, at each of our box corners, move around and make sure we end up back where we started
for _, corner in pairs(corners) do

	print("Checking counter-clockwise",corner)
	-- counter-clockwise
	local s,d = corner, directions.up
	local ns, nd = exists(s,d)
	print("Returns from exists 1:",ns,nd)
	s = assert(e)
	d = directions[dirmap[d].L]
	e, d = exists(u,d)
	s = assert(e)
	d = directions[dirmap[d].L]
	e, d = exists(u,d)
	s = assert(e)
	assert(s == corner,s .. " was not " .. corner)
end
]]

local function run(state, instructions)
	local function walk(state,n)
		print("Walking",state,n)
		for i = 1, n do
			local dir = directions[dirmap[state.direction].name]
			local newloc, newdir = open(state.location,dir)
			--local newloc, newdir = exists(state.location,dir)
			if newloc then
				print("Walked to",newloc)
				state.location = newloc
				state.direction = newdir
			else
				break
			end
		end
	end
	local function turn(state,dir)
		print("Turning",state)
		assert(type(state.location) == "string")
		assert(type(state.direction) == "number")
		state.direction = dirmap[state.direction][dir]
	end
	while #instructions > 0 do
		local ins = table.remove(instructions,1)
		if ins.type == "walk" then
			walk(state,ins.n)
		elseif ins.type == "turn" then
			turn(state,ins.n)
		end
	end
end
-- test that it works
local ghosts = {
	{1,51,rev_dirmap.up,"1L1L1"},
	{1,51,rev_dirmap.left,"1R1R1"},
	{1,100,rev_dirmap.up,"1R1R1"},
	{1,100,rev_dirmap.right,"1L1L1"},
	{1,101,rev_dirmap.up,"1L1L1"},
	{1,101,rev_dirmap.left,"1R1R1"},
	{1,150,rev_dirmap.up,"1R1R1"},
	{1,150,rev_dirmap.right,"1L1L1"},
	{50,51,rev_dirmap.left,"1L1L1"},
	{50,51,rev_dirmap.down,"1R1R1"},
	{50,100,rev_dirmap.right,"1R1R1"},
	{50,100,rev_dirmap.down,"1L1L1"},
	{50,150,rev_dirmap.right,"1R1R1"},
	{50,150,rev_dirmap.down,"1L1L1"},
	{51,51,rev_dirmap.left,"1R1R1"},
	{51,51,rev_dirmap.up,"1L1L1"},
	{51,100,rev_dirmap.up,"1R1R1"},
	{51,100,rev_dirmap.right,"1L1L1"},
	{100,51,rev_dirmap.left,"1L1L1"},
	{100,51,rev_dirmap.down,"1R1R1"},
	{100,100,rev_dirmap.right,"1R1R1"},
	{100,100,rev_dirmap.down,"1L1L1"},
	{101,1,rev_dirmap.up,"1L1L1"},
	{101,1,rev_dirmap.left,"1R1R1"},
	{101,50,rev_dirmap.up,"1R1R1"},
	{101,50,rev_dirmap.right,"1L1L1"},
	{101,51,rev_dirmap.left,"1R1R1"},
	{101,51,rev_dirmap.up,"1L1L1"},
	{101,100,rev_dirmap.right,"1L1L1"},
	{101,100,rev_dirmap.up,"1R1R1"},
	{150,1,rev_dirmap.left,"1L1L1"},
	{150,1,rev_dirmap.down,"1R1R1"},
	{150,50,rev_dirmap.right,"1R1R1"},
	{150,50,rev_dirmap.down,"1L1L1"},
	{150,51,rev_dirmap.left,"1L1L1"},
	{150,51,rev_dirmap.down,"1R1R1"},
	{150,100,rev_dirmap.right,"1R1R1"},
	{150,100,rev_dirmap.down,"1L1L1"}
}
--[[
for _,ghost in pairs(ghosts) do
	print("=========================")
	print("Checking location:",ghost)
	local c = parse_command(ghost[4])
	local locc = string.format("%d,%d",ghost[1],ghost[2])
	local istate = {
		location = locc,
		direction = ghost[3]
	}
	run(istate,c)
	assert(istate.location == locc)
end
os.exit(0)
]]

run(state,commands)
print(state)
local row, col = state.location:match("(%d+),(%d+)")
print((row*1000) + (col * 4) + state.direction)