advent-of-code/2018/14/main2.go

50 lines
1.3 KiB
Go

package main
import (
"fmt"
)
func completesTargetSequence(newElement byte) bool {
if target[foundDigits] == newElement {
foundDigits++
if foundDigits == len(target) {
return true
}
} else {
foundDigits = 0
}
return false
}
var target = [...]byte{9, 1, 9, 9, 0, 1}
var foundDigits = 0
func main() {
// Passing turns as the length here doesn’t work because it initializes 1 million bytes as 0 instead of allocating space so I can append later.
// RIP performance, but I consider this way more readable than the alternativ.
recipes := make([]byte, 0)
recipes = append(recipes, 3)
recipes = append(recipes, 7)
e1, e2 := 0, 1
for true {
firstRecipe, secondRecipe := recipes[e1], recipes[e2]
newRecipe := firstRecipe + secondRecipe
if newRecipe >= 10 {
recipes = append(recipes, 1)
newRecipe -= 10
if completesTargetSequence(1) {
break
}
}
recipes = append(recipes, newRecipe)
if completesTargetSequence(newRecipe) {
break
}
e1 = (e1 + int(firstRecipe) + 1) % len(recipes)
e2 = (e2 + int(secondRecipe) + 1) % len(recipes)
}
fmt.Println(len(recipes) - len(target))
}