AoC, Day 1, Part 1 (Solved)

2023/01/code.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"unicode"
+
+	"github.com/jpillora/puzzler/harness/aoc"
+)
+
+func main() {
+	aoc.Harness(run)
+}
+
+// on code change, run will be executed 4 times:
+// 1. with: false (part1), and example input
+// 2. with: true (part2), and example input
+// 3. with: false (part1), and user input
+// 4. with: true (part2), and user input
+// the return value of each run is printed to stdout
+func run(part2 bool, input string) any {
+	// when you're ready to do part 2, remove this "not implemented" block
+	if part2 {
+		return "not implemented"
+	}
+
+	sum := 0
+	for _, line := range strings.Split(input, "\n") {
+		var firstChar rune
+		var secondChar rune
+
+		for i := range line {
+			if unicode.IsNumber(firstChar) && unicode.IsNumber(secondChar) {
+				break
+			}
+
+			if !unicode.IsNumber(firstChar) && unicode.IsNumber([]rune(line)[i]) {
+				firstChar = []rune(line)[i]
+			}
+
+			if !unicode.IsNumber(secondChar) && unicode.IsNumber([]rune(line)[len(line)-i-1]) {
+				secondChar = []rune(line)[len(line)-i-1]
+			}
+		}
+
+		numberStr := fmt.Sprintf("%v%v", string(firstChar), string(secondChar))
+		number, _ := strconv.Atoi(numberStr)
+
+		sum += number
+	}
+
+	return sum
+}