# Libraries
+library(tidyverse)
+library(unglue)
+
+# Read input from file
+input <- read_lines("../input/day17.txt", skip_empty_rows = TRUE) |>
+ unglue_data(patterns = c(
+ "{label}: {value}"
+ ))
+
+
+
+
+
+
+
+
+Day 17
+Advent of Code: Worked Solutions
+Setup
+
+
+
+Part 1
+Initialize the machine from the text input:
+
+
+
+program <- input |>
+ filter(label == "Program") |>
+ pull(value) |>
+ str_split_1(",") |>
+ as.integer()
+
+A <- input |>
+ filter(label == "Register A") |>
+ pull(value) |>
+ as.integer()
+
+B <- input |>
+ filter(label == "Register B") |>
+ pull(value) |>
+ as.integer()
+
+C <- input |>
+ filter(label == "Register C") |>
+ pull(value) |>
+ as.integer()
+
+machine <- list(program = program, A = A, B = B, C = C, pointer = 0L, output = NULL)Define machine’s helper functions:
+
+
+
+combo <- function(machine, operand) {
+ case_match(operand,
+ 0 ~ 0,
+ 1 ~ 1,
+ 2 ~ 2,
+ 3 ~ 3,
+ 4 ~ machine$A,
+ 5 ~ machine$B,
+ 6 ~ machine$C
+ )
+}
+
+run_opcode <- function(machine, opcode, operand) {
+ func <- case_match(opcode,
+ 0 ~ "adv",
+ 1 ~ "bxl",
+ 2 ~ "bst",
+ 3 ~ "jnz",
+ 4 ~ "bxc",
+ 5 ~ "out",
+ 6 ~ "bdv",
+ 7 ~ "cdv"
+ )
+
+ get(func)(machine, operand)
+}
+
+run_machine <- function(machine) {
+ while (machine$pointer < length(machine$program)) {
+ opcode <- machine$program[machine$pointer + 1]
+ operand <- machine$program[machine$pointer + 2]
+ machine <- run_opcode(machine, opcode, operand)
+ }
+ print(machine$output)
+}Define the opcode functions:
+
+
+
+adv <- function(machine, operand) {
+ machine$A <- floor(machine$A / 2^combo(machine, operand))
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+bxl <- function(machine, operand) {
+ machine$B <- bitwXor(machine$B, operand)
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+bst <- function(machine, operand) {
+ machine$B <- combo(machine, operand) %% 8
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+jnz <- function(machine, operand) {
+ if (machine$A != 0)
+ machine$pointer <- operand
+ else
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+bxc <- function(machine, operand) {
+ machine$B <- bitwXor(machine$B, machine$C)
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+out <- function(machine, operand) {
+ machine$output <- str_c(
+ machine$output,
+ combo(machine, operand) %% 8,
+ sep = ","
+ )
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+bdv <- function(machine, operand) {
+ machine$B <- floor(machine$A / 2^combo(machine, operand))
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}
+
+cdv <- function(machine, operand) {
+ machine$C <- floor(machine$A / 2^combo(machine, operand))
+ machine$pointer <- machine$pointer + 2
+ return(machine)
+}Run on puzzle input:
+
+
+
+
+
+run_machine(machine)
+
+[1] "3,1,4,3,1,7,1,6,3"