feat: solve day 5 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: 9/24
+#### Stars: 10/24
 
 |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:|6<br>|7<br>|
+|1<br>:star::star:|2<br>:star::star:|3<br>:star::star:|4<br>:star::star:|5<br>:star::star:|6<br>|7<br>|
 |8<br>|9<br>|10<br>|11<br>|12<br>|||
 <!-- calendar-end -->

res/stats.json

@@ -17,7 +17,7 @@
     },
     "day05": {
         "puzzle1": true,
-        "puzzle2": false
+        "puzzle2": true
     },
     "day06": {
         "puzzle1": false,

src/day05/puzzle2.lua

@@ -1,7 +1,47 @@
+local strings = require "cc.strings"
 local puzzle2 = {}
 
 function puzzle2.solve(input)
-    return 0
+    local lines = strings.split(input, "\n")
+    local bounds = {}
+
+    for _, line in ipairs(lines) do
+        if line == "" then
+            break
+        end
+        local min, max = line:match("(%d+)%-(%d+)")
+        min = tonumber(min)
+        max = tonumber(max)
+        table.insert(bounds, {i=min, type="start"})
+        table.insert(bounds, {i=max, type="end"})
+    end
+
+    table.sort(bounds, function (a, b)
+        if a.i == b.i then
+            return a.type == "start" and b.type == "end"
+        end
+        return a.i < b.i
+    end)
+
+    local totalFresh = 0
+    local min = 0
+    local balance = 0
+
+    for _, bound in ipairs(bounds) do
+        if bound.type == "start" then
+            if balance == 0 then
+                min = bound.i
+            end
+            balance = balance + 1
+        else
+            balance = balance - 1
+            if balance == 0 then
+                totalFresh = totalFresh + bound.i - min + 1
+            end
+        end
+    end
+
+    return totalFresh
 end
 
 return puzzle2