day 19 part 2

day19/part2.lua

@@ -0,0 +1,173 @@
+#!/usr/bin/env luajit
+require("utils")
+require("pqueue")
+
+local scanners = {}
+local scanner = {}
+for line in io.lines(arg[3]) do
+	if #line == 0 then
+		table.insert(scanners, scanner)
+		scanner = {}
+	elseif char(line, 2) == "-" then
+	else
+		local x, y, z = unpack(split(line, ","))
+		local beacon = { x = tonumber(x)
+		               , y = tonumber(y)
+		               , z = tonumber(z) }
+		               -- , q = pqueue() }
+		table.insert(scanner, beacon)
+	end
+end
+table.insert(scanners, scanner)
+
+for _, scanner in pairs(scanners) do
+	for i = 1, #scanner do
+		for j = i + 1, #scanner do
+			local d = (scanner[i].x - scanner[j].x) ^ 2
+			        + (scanner[i].y - scanner[j].y) ^ 2
+			        + (scanner[i].z - scanner[j].z) ^ 2
+			-- scanner[i].q:add(d)
+			-- if #scanner[i].q.items > 4 then scanner[i].q:pop() end
+			-- scanner[j].q:add(d); scanner[j].q:pop()
+			-- if #scanner[j].q.items > 4 then scanner[j].q:pop() end
+		end
+	end
+end
+
+local function minp(a, b)
+	return { x = a.x - b.x, y = a.y - b.y, z = a.z - b.z }
+end
+
+local function addp(a, b)
+	return { x = a.x + b.x, y = a.y + b.y, z = a.z + b.z }
+end
+
+local rotations = { function(p) return { x =  p.x, y =  p.y, z =  p.z } end
+                  , function(p) return { x =  p.x, y =  p.z, z = -p.y } end
+                  , function(p) return { x =  p.x, y = -p.y, z = -p.z } end
+                  , function(p) return { x =  p.x, y = -p.z, z =  p.y } end
+                  , function(p) return { x =  p.y, y = -p.x, z =  p.z } end
+                  , function(p) return { x =  p.y, y =  p.z, z =  p.x } end
+                  , function(p) return { x =  p.y, y =  p.x, z = -p.z } end
+                  , function(p) return { x =  p.y, y = -p.z, z = -p.x } end
+                  , function(p) return { x = -p.x, y = -p.y, z =  p.z } end
+                  , function(p) return { x = -p.x, y = -p.z, z = -p.y } end
+                  , function(p) return { x = -p.x, y =  p.y, z = -p.z } end
+                  , function(p) return { x = -p.x, y =  p.z, z =  p.y } end
+                  , function(p) return { x = -p.y, y =  p.x, z =  p.z } end
+                  , function(p) return { x = -p.y, y = -p.z, z =  p.x } end
+                  , function(p) return { x = -p.y, y = -p.x, z = -p.z } end
+                  , function(p) return { x = -p.y, y =  p.z, z = -p.x } end
+                  , function(p) return { x =  p.z, y =  p.y, z = -p.x } end
+                  , function(p) return { x =  p.z, y =  p.x, z =  p.y } end
+                  , function(p) return { x =  p.z, y = -p.y, z =  p.x } end
+                  , function(p) return { x =  p.z, y = -p.x, z = -p.y } end
+                  , function(p) return { x = -p.z, y = -p.y, z = -p.x } end
+                  , function(p) return { x = -p.z, y = -p.x, z =  p.y } end
+                  , function(p) return { x = -p.z, y =  p.y, z =  p.x } end
+                  , function(p) return { x = -p.z, y =  p.x, z = -p.y } end
+                  }
+
+local function eqp(a, b)
+	return a.x == b.x and a.y == b.y and a.z == b.z
+end
+
+local function rotate(a, r)
+	local b = {}
+	for _, p in pairs(a) do
+		table.insert(b, r(p))
+	end
+	return b
+end
+
+local function move(a, d)
+	local b = {}
+	for _, p in pairs(a) do
+		table.insert(b, { x = p.x + d.x
+		                , y = p.y + d.y
+		                , z = p.z + d.z })
+	end
+	return b
+end
+
+local function similar(a, b)
+	local counter = 0
+	for i, pa in pairs(a) do
+		for j, pb in pairs(b) do
+			if eqp(pa, pb) then
+				counter = counter + 1
+				break
+			end
+		end
+		if counter >= 12 then
+			return counter
+		end
+	end
+	return 0
+end
+
+function compare(a, b)
+	for _, r in pairs(rotations) do
+		local br = rotate(b, r)
+		for _, pa1 in pairs(a) do
+			for _, pb1 in pairs(br) do
+				local d = minp(pa1, pb1)
+				local b_ = move(br, d)
+				if similar(a, b_) >= 12 then
+					return b_, d
+				end
+			end
+		end
+	end
+	return nil
+end
+
+local beacons = {}
+local counter = 0
+local function countbeacons(scanner)
+	for _, b in pairs(scanner) do
+		local xs = beacons[b.x] or {}
+		local ys = xs[b.y] or {}
+		if ys[b.z] == nil then
+			ys[b.z] = true
+			counter = counter + 1
+		end
+		xs[b.y] = ys
+		beacons[b.x] = xs
+	end
+end
+
+local compareWiths = { scanners[1] }
+local todos = { unpack(scanners, 2) }
+local locations = { { x=0, y=0, z=0 } }
+while #todos > 0 do
+	print(#todos)
+	local newCompareWiths = {}
+	local newtodos = {}
+	for _, todo in pairs(todos) do
+		local found, d = nil
+		for _, compareWith in pairs(compareWiths) do
+			found, d = compare(compareWith, todo)
+			if found then break end
+		end
+		if found then
+			table.insert(newCompareWiths, found)
+			table.insert(locations, d)
+		else
+			table.insert(newtodos, todo)
+		end
+	end
+	todos = newtodos
+	compareWiths = newCompareWiths
+end
+
+local max = 0
+for i = 1, #locations do
+	for j = i + 1, #locations do
+		local d = math.abs(locations[i].x - locations[j].x)
+		        + math.abs(locations[i].y - locations[j].y)
+		        + math.abs(locations[i].z - locations[j].z)
+		if d > max then max = d end
+	end
+end
+print(max)