Added solutions for 18th day: snailfish arithmetic

2021/18/first.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"git.adyxax.org/aoc/2021/18/pairs"
+)
+
+func main() {
+	parser := pairs.NewParser(os.Stdin)
+	pair, err := parser.Parse()
+	if err != nil {
+		log.Fatalf("%w", err)
+	}
+	for {
+		pair2, err := parser.Parse()
+		if err != nil {
+			break
+		}
+		pair = pair.Add(pair2)
+	}
+	fmt.Println(pair)
+	pair.Reduce()
+	fmt.Println(pair)
+	fmt.Println(pair.Magnitude())
+}