Advent of Code - Day 10: Cathode-Ray Tube

library(tidyr)
library(dplyr)
library(readr)
library(stringr)

Part 1

Input

sample <-"input.txt"

Code

input <- read_delim(file = sample, delim =  " ",col_names = c("name","value")) %>%
  replace_na(replace = list(value = 0))

result <- 
  input %>%
  mutate(cycle = cumsum(case_when(name == "addx" ~2,
                             TRUE ~ 1)),
         register = 1 + lag(cumsum(value),1)) %>%
  complete(cycle = 1:240) %>%
  fill(register,.direction = "up") %>%
    mutate(signal = cycle * register)

 result %>%
  filter(cycle %in% seq(20, 220, by=40)) %>%
  summarise(sum(signal))

result %>%
  mutate(row = (cycle -1) %/% 40,
         col = (cycle -1) %% 40,
         pixel = ifelse(col >= register -1 & col <= register +1,"#",".")) %>%
  group_by(row) %>%
  summarise(paste0(pixel, collapse=""))