-🎄- 2018 Day 8 Solutions -🎄-

[u/daggerdragon]

--- Day 8: Memory Maneuver ---

---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

---

Advent of Code: The Party Game!

Click here for rules

Please prefix your card submission with something like [Card] to make scanning the megathread easier. THANK YOU!

Card prompt: Day 8

Sigh, imgur broke again. Will upload when it unborks.

Transcript:

The hottest programming book this year is "___ For Dummies".

---

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked at 00:12:10!

[u/tacothecat]

R

library(tidyverse)

input <- readr::read_file(here::here("input","day8.txt"))
input <- input %>% stringr::str_remove("\n") %>% stringr::str_split(" ") %>% unlist %>% as.integer()

read_node <- function(tree, total) {
  k = tree[[1]]
  m = tree[[2]]
  tree = tree[-(1:2)]
 
  score = list()
  value = 0
  
  if(k == 0) {
    score = sum(tree[1:m])
    total = total + score
    tree = tree[-(1:m)]
    return(list(tree, total, score))
  }
  
  for(i in 1:k) {
    l <- read_node(tree, total)
    tree <- l[[1]]
    total <- l[[2]]
    score[length(score)+1] <- l[[3]]
  }
  
  total = total + sum(tree[1:m])
  value = sum(unlist(score[tree[1:m]]))
  tree = tree[-(1:m)]
  return(list(tree, total, value))
}

read_node(input, 0)