08: I Heard You Like Registers

library(mistlecode)

To install `mistlecode` yourself, run `devtools::install_github('guslipkin/mistlecode')`.

 Also loading:  cipheR data.table dplyr purrr slider stringr tidyverse glue rlang R6

dt <- fread("input.txt")

Part 1

This was so much fun. I like that I had to hack around my computer a bit with the proc function to do the actual processing, but it’s good to keep in my back pocket for later.

registers <- 
  dt$V1 |>
  unique() |>
  sort()
registers <- 
  rep(0L, length(registers)) |>
  as.list() |>
  `names<-`(registers)

functions <- list(
  "proc" = \(x, y) {
    x <- str_match(x, "([a-z]+) (inc|dec) (-?[0-9]+) if (.*)")[1,-1]
    iff <- eval(parse(text = glue("self${x[4]}")))
    if (iff) {
      self[[x[1]]] <- self[[x[2]]](x[1], as.integer(x[3]))
    }
    private$.inc()
  },
  "inc" = \(x, y) {
    self[[x]] <- self[[x]] + y
  },
  "dec" = \(x, y) {
    self[[x]] <- self[[x]] - y
  }
)

x <- 
  readLines("input.txt") |>
  add_processor()
a <- create_assembly(registers, functions)$run(x)
as.list(a)[names(registers)] |>
  unlist() |>
  max()

[1] 2971

Part 2

Hmmm. Okay. Small register and function mods and we’re good to go!

registers$maximum_value <- 0L

functions$proc <- \(x, y) {
  x <- str_match(x, "([a-z]+) (inc|dec) (-?[0-9]+) if (.*)")[1,-1]
    iff <- eval(parse(text = glue("self${x[4]}")))
    if (iff) {
      self[[x[1]]] <- self[[x[2]]](x[1], as.integer(x[3]))
      if (self[[x[1]]] > self$maximum_value) self$maximum_value <- self[[x[1]]]
    }
    private$.inc()
}

create_assembly(registers, functions)$run(x, target = "maximum_value")

[1] 4254