day 11

year25/day11/day.go

@@ -0,0 +1,101 @@
+package day11
+
+import (
+	"fmt"
+	"strings"
+
+	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/aoc"
+	"git.bizdoc.ro/private/devkit.git/collections/dsa"
+)
+
+func parseInput(ctx aoc.Context) (map[string][]string, error) {
+	graph := make(map[string][]string)
+
+	s := ctx.Scanner()
+	for s.Scan() {
+		line := s.Text()
+		parts := strings.Split(line, ": ")
+		key := parts[0]
+		graph[key] = strings.Split(parts[1], " ")
+	}
+	if err := s.Err(); err != nil {
+		return nil, fmt.Errorf("scanner error: %w", err)
+	}
+	return graph, nil
+}
+
+func Part1(ctx aoc.Context) (int, error) {
+	graph, err := parseInput(ctx)
+	if err != nil {
+		return 0, err
+	}
+
+	const start = "you"
+	const end = "out"
+
+	stack := dsa.NewStack[string]()
+	stack.Push(start)
+	var pathsToEnd int
+	for !stack.IsEmpty() {
+		this := stack.Pop()
+		for _, next := range graph[this] {
+			stack.Push(next)
+		}
+		if this == end {
+			pathsToEnd += 1
+		}
+	}
+
+	return pathsToEnd, nil
+}
+
+func Part2(ctx aoc.Context) (uint64, error) {
+	graph, err := parseInput(ctx)
+	if err != nil {
+		return 0, err
+	}
+
+	type Item struct {
+		DAC, FFT bool
+		Name     string
+	}
+	cache := make(map[Item]uint64)
+
+	var recursion func(current Item, end string) uint64
+	recursion = func(current Item, end string) uint64 {
+		if current.Name == end {
+			return bool2int(current.DAC && current.FFT)
+		}
+
+		switch current.Name {
+		case "dac":
+			current.DAC = true
+		case "fft":
+			current.FFT = true
+		}
+
+		var sum uint64
+		for _, next := range graph[current.Name] {
+			current.Name = next
+
+			paths, ok := cache[current]
+			if !ok {
+				paths = recursion(current, end)
+				cache[current] = paths
+			}
+			sum += paths
+		}
+		return sum
+	}
+	return recursion(Item{DAC: false, FFT: false, Name: "svr"}, "out"), nil
+}
+
+func bool2int(b bool) uint64 {
+	var i uint64
+	if b {
+		i = 1
+	} else {
+		i = 0
+	}
+	return i
+}

year25/day11/day_test.go

@@ -0,0 +1,27 @@
+package day11
+
+import (
+	"testing"
+
+	"git.bizdoc.ro/gabi-public/Advent-of-Code.git/tests"
+)
+
+func TestPart1Example(t *testing.T) {
+	const want = 5
+	tests.Test(t, "example.txt", tests.Handler(Part1), want)
+}
+
+func TestPart1(t *testing.T) {
+	const want = 764
+	tests.Test(t, "input.txt", tests.Handler(Part1), want)
+}
+
+func TestPart2Example(t *testing.T) {
+	const want = 2
+	tests.Test(t, "example_part2.txt", tests.Handler(Part2), want)
+}
+
+func TestPart2(t *testing.T) {
+	const want = 462444153119850
+	tests.Test(t, "input.txt", tests.Handler(Part2), want)
+}