Advent of Code 2020-05 with R

library(magrittr) # Read the data ipt <- read.table("2020-05-aoc.txt", header = FALSE, stringsAsFactors = FALSE) library(magrittr) # For chunk2 library(stackoverflow) library(purrr, warn.conflicts = FALSE) get_chunks <- function(vec, ext, nms){ # split the vec in two, set the name, and extract the correct chunk chunk2(vec, 2) %>% setNames(nms) %>% pluck(ext) } # Prefilling the functions with the correct nms get_bf<- partial(get_chunks, nms = c("F", "B")) get_lr <- partial(get_chunks, nms = c("L", "R")) get_all <- function(entry){ entry <- strsplit(entry, "")[[1]] # Doing the get_bf on the 7 first letters row <- get_bf(0:127, entry[1]) %>% get_bf(entry[2]) %>% get_bf(entry[3]) %>% get_bf(entry[4]) %>% get_bf(entry[5]) %>% get_bf(entry[6]) %>% get_bf(entry[7]) # Doing the get_lr on the 3 last letters column <- get_lr(0:7, entry[8]) %>% get_lr(entry[9]) %>% get_lr(entry[10]) # Computing the seat id seatid <- (row * 8) + column return(seatid) } # Getting the max map_dbl(ipt$V1, get_all) %>% max() ## [1] 864 

library(dplyr, warn.conflicts = FALSE) # Extracting all the ids map_dbl(ipt$V1, get_all) %>% # Sorting them in order and turning into a df sort() %>% data.frame( x = . ) %>% # Computing the diff between all ids mutate( y = lag(x), diff = x - y ) %>% # My passport ID will be the one between the IDS  # of diff != 1 filter( diff != 1 ) ## x y diff ## 1 740 738 2