feat: solve day 8 puzzle 2

src/day08/puzzle2.lua

@@ -1,7 +1,52 @@
+local utils = require "utils"
+local puzzle1 = require(SRC_PATH .. "/day08/puzzle1")
 local puzzle2 = {}
 
 function puzzle2.solve(input)
-    return 0
+    local boxes = {}
+
+    local lines = utils.splitLines(input)
+
+    for i, line in ipairs(lines) do
+        local x, y, z = line:match("(%d+),(%d+),(%d+)")
+        table.insert(boxes, {x=x, y=y, z=z, i=i, circuit=i})
+    end
+
+    local dists = {}
+    local circuits = {}
+
+    for i, box1 in ipairs(boxes) do
+        circuits[i] = i
+        for j=i+1, #boxes do
+            local box2 = boxes[j]
+            table.insert(dists, {
+                i=i,
+                j=j,
+                dist=puzzle1.dist(box1, box2)
+            })
+        end
+    end
+
+    table.sort(dists, function (a, b)
+        return a.dist < b.dist
+    end)
+
+    for _, d in ipairs(dists) do
+        local circ1 = circuits[d.i]
+        local circ2 = circuits[d.j]
+        
+        local connex = true
+        for k, v in pairs(circuits) do
+            if v == circ2 then
+                circuits[k] = circ1
+            elseif v ~= circ1 then
+                connex = false
+            end
+        end
+        if connex then
+            return boxes[d.i].x * boxes[d.j].x
+        end
+    end
 end
 
 return puzzle2