feat: solve day 7 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: 12/24
+#### Stars: 14/24
 
 |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>|
+|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>|9<br>|10<br>|11<br>|12<br>|||
 <!-- calendar-end -->

res/examples/day07.txt

@@ -0,0 +1,16 @@
+.......S.......
+...............
+.......^.......
+...............
+......^.^......
+...............
+.....^.^.^.....
+...............
+....^.^...^....
+...............
+...^.^...^.^...
+...............
+..^...^.....^..
+...............
+.^.^.^.^.^...^.
+...............

res/stats.json

@@ -24,8 +24,8 @@
         "puzzle2": true
     },
     "day07": {
-        "puzzle1": false,
-        "puzzle2": false
+        "puzzle1": true,
+        "puzzle2": true
     },
     "day08": {
         "puzzle1": false,

src/day07/puzzle1.lua

@@ -0,0 +1,34 @@
+local utils = require "utils"
+
+local puzzle1 = {}
+
+function puzzle1.solve(input)
+    local lines = utils.splitLines(input)
+
+    local beams = {}
+    local totalSplits = 0
+
+    for i, line in ipairs(lines) do
+        local newBeams = {}
+        if i == 1 then
+            newBeams[line:find("S")] = true
+        else
+            for j=1, #line do
+                if beams[j] then
+                    if line:sub(j, j) == "^" then
+                        totalSplits = totalSplits + 1
+                        newBeams[j - 1] = true
+                        newBeams[j + 1] = true
+                    else
+                        newBeams[j] = true
+                    end
+                end
+            end
+        end
+        beams = newBeams
+    end
+
+    return totalSplits
+end
+
+return puzzle1

src/day07/puzzle2.lua

@@ -0,0 +1,37 @@
+local utils = require "utils"
+
+local puzzle2 = {}
+
+function puzzle2.solve(input)
+    local lines = utils.splitLines(input)
+
+    local beams = {}
+
+    for i, line in ipairs(lines) do
+        local newBeams = {}
+        if i == 1 then
+            newBeams[line:find("S")] = 1
+        else
+            for j=1, #line do
+                if beams[j] then
+                    if line:sub(j, j) == "^" then
+                        newBeams[j - 1] = (newBeams[j - 1] or 0) + beams[j]
+                        newBeams[j + 1] = (newBeams[j + 1] or 0) + beams[j]
+                    else
+                        newBeams[j] = (newBeams[j] or 0) + beams[j]
+                    end
+                end
+            end
+        end
+        beams = newBeams
+    end
+
+    local finalBeams = 0
+    for _, v in pairs(beams) do
+        finalBeams = finalBeams + v
+    end
+
+    return finalBeams
+end
+
+return puzzle2