AoC Day 4, Part 1 (Solved)

2023/04/code.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"regexp"
+	"strings"
+
+	"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"
+	}
+	// solve part 1 here
+
+	gameIdRxp := regexp.MustCompile(`Card +(?P<ID>\d+):  ?(?P<Winning>.*) \|  ?(?P<Drawn>.*)`)
+
+	sum := 0
+	for _, line := range strings.Split(input, "\n") {
+
+		matches := gameIdRxp.FindStringSubmatch(line)
+		if len(matches) == 0 {
+			continue
+		}
+
+		winning := strings.Split(matches[2], " ")
+		drawn := strings.Split(matches[3], " ")
+
+		points := 0
+		for _, win := range winning {
+			if win == "" {
+				continue
+			}
+
+			for _, draw := range drawn {
+				if win == draw {
+					if points == 0 {
+						points = 1
+					} else {
+						points = points * 2
+					}
+				}
+			}
+		}
+		sum += points
+	}
+
+	return sum
+}