feat: solve day 3 puzzle 1

src/day03/puzzle1.lua

@@ -0,0 +1,41 @@
+local utils = require("utils")
+local puzzle1 = {}
+
+function puzzle1.bankJoltages(bank)
+    local joltages = {}
+    for i=1, #bank do
+        table.insert(joltages, tonumber(bank:sub(i, i)))
+    end
+    return joltages
+end
+
+function puzzle1.findMaxJoltage(bank)
+    local maxTens = 0
+    local maxJoltage = 0
+    local joltages = puzzle1.bankJoltages(bank)
+
+    for i, tens in ipairs(joltages) do
+        if tens > maxTens then
+            for j=i+1, #joltages do
+                local ones = joltages[j]
+                local joltage = tens * 10 + ones
+                if joltage > maxJoltage then
+                    maxTens = tens
+                    maxJoltage = joltage
+                end
+            end
+        end
+    end
+    return maxJoltage
+end
+
+function puzzle1.solve(input)
+    local banks = utils.splitLines(input)
+    local totalJoltage = 0
+    for _, bank in ipairs(banks) do
+        totalJoltage = totalJoltage + puzzle1.findMaxJoltage(bank)
+    end
+    return totalJoltage
+end
+
+return puzzle1

src/day03/puzzle2.lua

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