Day22

2024/gareth/day22/day22.go

@@ -0,0 +1,112 @@
+package day22
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type Queue struct {
+	data []int
+	size int
+}
+
+func NewQueue(size int) *Queue {
+	return &Queue{
+		data: make([]int, 0, size),
+		size: size,
+	}
+}
+
+func (queue *Queue) Push(value int) {
+	if len(queue.data) == queue.size {
+		queue.data = queue.data[1:]
+	}
+	queue.data = append(queue.data, value)
+}
+
+func (queue *Queue) Get() []int {
+	return queue.data
+}
+
+func (queue *Queue) String() string {
+	strs := make([]string, len(queue.data))
+	for i, val := range queue.data {
+		strs[i] = fmt.Sprintf("%d", val)
+	}
+	return strings.Join(strs, ", ")
+}
+
+func Part1(input string) int {
+	secretNumbers := parseInput(input)
+
+	total := 0
+	for _, number := range secretNumbers {
+		for i := 0; i < 2000; i++ {
+			number = getNextNumber(number)
+		}
+		total += number
+	}
+	return total
+}
+
+func Part2(input string) int {
+	secretNumbers := parseInput(input)
+	memo := make(map[string]int)
+
+	for _, number := range secretNumbers {
+		seen := make(map[string]bool)
+		queue := NewQueue(4)
+		prevNumber := secretNumbers[0] % 10
+
+		for i := 0; i < 2000; i++ {
+			singleNumber := number % 10
+			cost := singleNumber - prevNumber
+			queue.Push(cost)
+			if i > 3 {
+				if _, ok := seen[queue.String()]; !ok {
+					memo[queue.String()] += singleNumber
+					seen[queue.String()] = true
+				}
+			}
+			prevNumber = singleNumber
+			number = getNextNumber(number)
+		}
+	}
+	return maxMapValue(memo)
+}
+
+func parseInput(input string) []int {
+	parts := strings.Split(input, "\n")
+	secretNumbers := []int{}
+	for _, part := range parts {
+		num, _ := strconv.Atoi(part)
+		secretNumbers = append(secretNumbers, num)
+	}
+
+	return secretNumbers
+}
+
+func getNextNumber(number int) int {
+	step1 := (number * 64) ^ number
+	step1 = step1 % 16777216
+
+	step2 := (step1 / 32) ^ step1
+	step2 = step2 % 16777216
+
+	step3 := (step2 * 2048) ^ step2
+	step3 = step3 % 16777216
+
+	return step3
+}
+
+func maxMapValue(memo map[string]int) int {
+	maxValue := 0
+
+	for _, value := range memo {
+		if value > maxValue {
+			maxValue = value
+		}
+	}
+	return maxValue
+}

2024/gareth/day22/day22_test.go

@@ -0,0 +1,23 @@
+package day22
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(`1
+10
+100
+2024`)
+	assert.Equal(t, 37327623, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(`1
+2
+3
+2024`)
+	assert.Equal(t, 23, r)
+}

2024/gareth/main.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	"aoc2024/day21"
+	"aoc2024/day22"
 	"fmt"
 	"os"
 	"time"
@@ -9,9 +9,9 @@ import (
 
 func main() {
 	start := time.Now()
-	data, _ := os.ReadFile("day21/input.txt")
-	fmt.Printf("part 1: %d\n", day21.Part1(string(data)))
-	fmt.Printf("part 2: %d\n", day21.Part2(string(data)))
+	data, _ := os.ReadFile("day22/input.txt")
+	fmt.Printf("part 1: %d\n", day22.Part1(string(data)))
+	fmt.Printf("part 2: %d\n", day22.Part2(string(data)))
 	elapsed := time.Since(start)
 	fmt.Printf("Execution time: %s\n", elapsed)
 }