feat: solve day 9 puzzle 1

README.md

@@ -8,10 +8,10 @@ This project can also be run using the amazing [CraftOS-PC emulator](https://git
 ## Progress
 
 <!-- calendar-start -->
-#### Stars: 16/24
+#### Stars: 17/24
 
 |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>|10<br>|11<br>|12<br>|||
+|8<br>:star::star:|9<br>:star:|10<br>|11<br>|12<br>|||
 <!-- calendar-end -->

res/examples/day09.txt

@@ -0,0 +1,8 @@
+7,1
+11,1
+11,7
+9,7
+9,5
+2,5
+2,3
+7,3

res/stats.json

@@ -32,7 +32,7 @@
         "puzzle2": true
     },
     "day09": {
-        "puzzle1": false,
+        "puzzle1": true,
         "puzzle2": false
     },
     "day10": {

src/day09/puzzle1.lua

@@ -0,0 +1,30 @@
+local utils = require "utils"
+local puzzle1 = {}
+
+function puzzle1.area(tile1, tile2)
+    local dx = math.abs(tile2.x - tile1.x) + 1
+    local dy = math.abs(tile2.y - tile1.y) + 1
+    return dx * dy
+end
+
+function puzzle1.solve(input)
+    local lines = utils.splitLines(input)
+    local tiles = {}
+
+    for _, line in ipairs(lines) do
+        local x, y = line:match("(%d+),(%d+)")
+        table.insert(tiles, {x=tonumber(x), y=tonumber(y)})
+    end
+
+    local maxArea = 0
+    for i, tile1 in ipairs(tiles) do
+        for j=i+1, #tiles do
+            local tile2 = tiles[j]
+            local area = puzzle1.area(tile1, tile2)
+            maxArea = math.max(maxArea, area)
+        end
+    end
+    return maxArea
+end
+
+return puzzle1

src/day09/puzzle2.lua

@@ -0,0 +1,7 @@
+local puzzle2 = {}
+
+function puzzle2.solve(input)
+    return 0
+end
+
+return puzzle2