Day 10: Elves Look, Elves Say

Reference

library(tidyverse)

input <- "1321131112"

Part One

forty <- input

for (i in 1:40) {
    forty <- forty |> 
        str_split_1(pattern = "") |> 
        rle() |> 
        unlist() |> 
        matrix(nrow = 2, byrow = TRUE) |> 
        str_flatten()
}

str_length(forty) |> cat()
## 492982

Part Two

fifty <- input

for (i in 1:50) {
    fifty <- fifty |> 
        str_split_1(pattern = "") |> 
        rle() |> 
        unlist() |> 
        matrix(nrow = 2, byrow = TRUE) |> 
        str_flatten()
}

str_length(fifty) |> cat()
## 6989950