Day 11. part 2.

data.go

@@ -33,3 +33,6 @@ var Day09Data string
 
 //go:embed day_10/data.txt
 var Day10Data string
+
+//go:embed day_11/data.txt
+var Day11Data string

day_11/data.txt

@@ -0,0 +1 @@
+64554 35 906 6 6960985 5755 975820 0

day_11/example_data.txt

@@ -0,0 +1 @@
+125 17

day_11/solution.go

@@ -0,0 +1,73 @@
+package day_11
+
+import (
+	"strconv"
+	"strings"
+)
+
+type Stones map[uint64]uint64
+
+// task:https://adventofcode.com/2024/day/11
+func SolveBasic(input string) int {
+	stones := load(input)
+
+	for i := 0; i < 25; i++ {
+		stones = blink(stones)
+	}
+
+	sum := uint64(0)
+	for _, st := range stones {
+		sum += st
+	}
+	return int(sum)
+}
+
+// task:https://adventofcode.com/2024/day/11#part2
+func SolveComplex(input string) int {
+	stones := load(input)
+
+	for i := 0; i < 75; i++ {
+		stones = blink(stones)
+	}
+
+	sum := uint64(0)
+	for _, st := range stones {
+		sum += st
+	}
+	return int(sum)
+}
+
+func blink(before Stones) Stones {
+	after := Stones{}
+	for stone, count := range before {
+		if stone == 0 {
+			after[1] += count
+		} else if val := fromUint(stone); len(val)%2 == 0 {
+			after[parseUint(val[:len(val)/2])] += count
+			after[parseUint(val[len(val)/2:])] += count
+		} else {
+			after[stone*2024] += count
+		}
+	}
+	return after
+}
+
+func fromUint(stone uint64) string {
+	return strconv.FormatUint(stone, 10)
+}
+
+func load(input string) Stones {
+	stones := Stones{}
+	for _, substring := range strings.Split(input, " ") {
+		stones[parseUint(substring)]++
+	}
+	return stones
+}
+
+func parseUint(substring string) uint64 {
+	if val, err := strconv.ParseUint(substring, 10, 64); err == nil {
+		return val
+	} else {
+		panic(err)
+	}
+}

day_11/solution_test.go

@@ -0,0 +1,17 @@
+package day_11_test
+
+import (
+	"advent_of_code_2024/day_11"
+	_ "embed"
+	"testing"
+)
+
+//go:embed example_data.txt
+var ExampleData string
+
+func TestBasicSolutionExample(t *testing.T) {
+	result := day_11.SolveBasic(ExampleData)
+	if result != 55312 {
+		t.Fatalf("Expected 55312 received %d", result)
+	}
+}

main.go

@@ -11,6 +11,7 @@ import (
 	"advent_of_code_2024/day_08"
 	"advent_of_code_2024/day_09"
 	"advent_of_code_2024/day_10"
+	"advent_of_code_2024/day_11"
 	_ "embed"
 	"fmt"
 	"os"
@@ -60,6 +61,10 @@ func main() {
 		fmt.Printf("Day 10. Basic: %d\n", day_10.SolveBasic(Day10Data)) //
 	case "10-complex":
 		fmt.Printf("Day 10. Complex: %d\n", day_10.SolveComplex(Day10Data)) //
+	case "11-basic":
+		fmt.Printf("Day 11. Basic: %d\n", day_11.SolveBasic(Day11Data)) //
+	case "11-complex":
+		fmt.Printf("Day 11. Complex: %d\n", day_11.SolveComplex(Day11Data)) //
 	}
 }