advent of code 1

gistfile1.txt

captcha <- function(x){
  
  #input 1122
  #return 3
  
  #input 1111
  #return 4
  
  first_digit <- substr(x,1,1)
  x <- paste0(x, first_digit)
  t <- vector(mode = "character")
  
  for (i in 1:(nchar(x)-1)){
    current_digit <- substr(x,i,i)
    next_digit <- substr(x, i+1, i+1)
    if (current_digit == next_digit){
      t <- append(t, next_digit)
    }
  }
  
  nums_to_add <- as.numeric(t)
  return(sum(nums_to_add))
}

x is the input stored as a character, since R has a maximum value for numbers