day_03.r

data <- readLines("data_03.txt")
letters_all <- c(letters,LETTERS)


process_line <- function(x){
  this_line <- data[x]
  sl = nchar(this_line)
  str1 <- substr(this_line,1,sl/2)
  str2 <- substr(this_line,(sl/2)+1,sl)
  chars1 <- strsplit(str1,"")[[1]]
  chars2 <- strsplit(str2,"")[[1]]
  dbl <- intersect(chars1,chars2)
  score <- which(letters_all == dbl)
  score
}

out <- lapply(1:length(data),process_line)
total <- sum(unlist(out))
print(total)

process_threes <- function(x){
  l1 <- strsplit(data[x],"")[[1]]
  l2 <- strsplit(data[x+1],"")[[1]]
  l3 <- strsplit(data[x+2],"")[[1]]

  this_char <- intersect(intersect(l1,l2),l3) 
  score <- which(letters_all == this_char)
  score
}

out <- lapply(seq(from=1,to=length(data),by=3),process_threes)
total <- sum(unlist(out))
print(total)