feat: solve day 11 puzzle 2

README.md

@@ -8,10 +8,10 @@ This project can also be run using the amazing [CraftOS-PC emulator](https://git
 ## Progress
 
 <!-- calendar-start -->
-#### Stars: 19/24
+#### Stars: 20/24
 
 |Mon|Tue|Wed|Thu|Fri|Sat|Sun|
 |:-:|:-:|:-:|:-:|:-:|:-:|:-:|
 |1<br>:star::star:|2<br>:star::star:|3<br>:star::star:|4<br>:star::star:|5<br>:star::star:|6<br>:star::star:|7<br>:star::star:|
-|8<br>:star::star:|9<br>:star:|10<br>:star:|11<br>:star:|12<br>|||
+|8<br>:star::star:|9<br>:star:|10<br>:star:|11<br>:star::star:|12<br>|||
 <!-- calendar-end -->

res/examples/day11.txt

@@ -1,10 +1,13 @@
-aaa: you hhh
-you: bbb ccc
-bbb: ddd eee
-ccc: ddd eee fff
-ddd: ggg
-eee: out
-fff: out
+svr: aaa bbb
+aaa: fft
+fft: ccc
+bbb: tty
+tty: ccc
+ccc: ddd eee
+ddd: hub
+hub: fff
+eee: dac
+dac: fff
+fff: ggg hhh
 ggg: out
-hhh: ccc fff iii
-iii: out
+hhh: out

res/examples/day11_1.txt

@@ -0,0 +1,10 @@
+aaa: you hhh
+you: bbb ccc
+bbb: ddd eee
+ccc: ddd eee fff
+ddd: ggg
+eee: out
+fff: out
+ggg: out
+hhh: ccc fff iii
+iii: out

res/stats.json

@@ -41,7 +41,7 @@
     },
     "day11": {
         "puzzle1": true,
-        "puzzle2": false
+        "puzzle2": true
     },
     "day12": {
         "puzzle1": false,

src/day11/puzzle2.lua

@@ -1,7 +1,49 @@
+local strings = require "cc.strings"
+local utils = require "utils"
 local puzzle2 = {}
 
+local cache = {}
+
+function puzzle2.countPaths(edges, startDev, endDev, dac, fft)
+    dac = dac or false
+    fft = fft or false
+    local key = startDev .. "-" .. endDev .. "-" .. tostring(dac) .. "-" .. tostring(fft)
+    if cache[key] then
+        return cache[key]
+    end
+    if startDev == endDev then
+        if dac and fft then
+            return 1
+        else
+            return 0
+        end
+    end
+    local outs = edges[startDev]
+    local total = 0
+    for _, out in ipairs(outs) do
+        local dac2 = dac
+        local fft2 = fft
+        if out == "dac" then
+            dac2 = true
+        elseif out == "fft" then
+            fft2 = true
+        end
+        total = total + puzzle2.countPaths(edges, out, endDev, dac2, fft2)
+    end
+    cache[key] = total
+    return total
+end
+
 function puzzle2.solve(input)
-    return 0
+    local lines = utils.splitLines(input)
+    local outputs = {}
+
+    for _, line in ipairs(lines) do
+        local device, outs = line:match("(.+): (.+)")
+        outputs[device] = strings.split(outs, " ")
+    end
+
+    return puzzle2.countPaths(outputs, "svr", "out")
 end
 
 return puzzle2