2023 advent of code day 9

day_9.R

# first star
input <- type.convert(strsplit(readLines("puzzle_input.txt"), "\\s"), as.is = TRUE)
predict <- function(element) {
  new_element <- element[length(element)]
  while(length(element != 0) > 0) {
    element <- diff(element)
    new_element <- c(new_element, element[length(element)])
  }
  sum(new_element)
}

sum(sapply(input, predict))

# second star
sum(sapply(input, function(x){predict(rev(x))}))