2024 Day 22 Complete!

2024/day22/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"fmt"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToIntSlice()
+	part1(inp)
+	fmt.Println()
+	part2(inp)
+}
+
+func part1(inp []int) {
+	var total int
+	for i := range inp {
+		total += steps(inp[i], 2000)
+	}
+	fmt.Println("# Part 1")
+	fmt.Println(total)
+}
+
+var cache map[int]map[string]int
+
+func part2(inp []int) {
+	fmt.Println("# Part 2")
+	cache = make(map[int]map[string]int)
+	for i := range inp {
+		wrk := inp[i]
+		cache[inp[i]] = make(map[string]int)
+		s := Seq{}
+		for n := 0; n < 2000; n++ {
+			next := step(wrk)
+			seqChg := (next % 10) - (wrk % 10)
+			s.Add(seqChg)
+			if s.Len() == 4 {
+				if _, ok := cache[inp[i]][s.String()]; !ok {
+					cache[inp[i]][s.String()] = worth(next)
+				}
+			}
+			wrk = next
+		}
+	}
+	var best int
+	var bestKey string
+	checkedKeys := make(map[string]bool)
+	for i := range inp {
+		if i > 0 {
+			h.ClearProgress()
+		}
+		h.PrintProgress(i, len(inp))
+		for k := range cache[inp[i]] {
+			if _, ok := checkedKeys[k]; ok {
+				continue
+			}
+			var total int
+			for j := range inp {
+				total += cache[inp[j]][k]
+			}
+			if total > best {
+				best = total
+				bestKey = k
+			}
+			checkedKeys[k] = true
+		}
+	}
+	fmt.Println()
+	fmt.Println("Most Bananas:", best, bestKey)
+}
+
+const prune = 16777216
+
+func steps(n, cnt int) int {
+	for i := 0; i < cnt; i++ {
+		n = step(n)
+	}
+	return n
+}
+
+func step(n int) int {
+	n ^= (n * 64)
+	n %= prune
+	n ^= (n / 32)
+	n %= prune
+	n ^= (n * 2048)
+	n %= prune
+	return n
+}
+
+func worth(n int) int {
+	return n % 10
+}
+
+type Seq struct {
+	s []int
+}
+
+func (s *Seq) Len() int { return len(s.s) }
+
+func (s *Seq) Add(n int) {
+	if len(s.s) >= 4 {
+		s.s = append(s.s[1:], n)
+	} else {
+		s.s = append(s.s, n)
+	}
+}
+
+func (s Seq) String() string {
+	var ret string
+	for i := range s.s {
+		ret = fmt.Sprintf("%s,%d", ret, s.s[i])
+	}
+	return ret[1:]
+}

2024/day22/testinput

@@ -0,0 +1,4 @@
+1
+10
+100
+2024

2024/day22/testinput2

@@ -0,0 +1,4 @@
+1
+2
+3
+2024

helpers/helpers.go

@@ -228,6 +228,10 @@ func PrintProgress(curr, total int) {
 	fmt.Print("]")
 }
 
+func ClearProgress() {
+	fmt.Print("\b\b\b\b\b\b\b\b\b\b\b\b")
+}
+
 // StringPermutations takes a string and returns all permutations of it
 func StringPermutations(str string) []string {
 	perms := stringPermHelper(str, 0)