3 files changed, 83 insertions(+), 0 deletions(-)

A 3/lex.mll
A 3/t1.ml
A 3/t2.ml

@@ 0,0 1,14 @@
+{
+type token =
+	| Str of string
+	| Eof
+}
+
+rule token = parse
+	| ['a'-'z''A'-'Z']+ '\n' as str {
+		Str (
+			String.length str - 1
+				|> String.sub str 0
+		)
+	}
+	| eof { Eof }

@@ 0,0 1,33 @@
+open Lex
+
+module S = Set.Make(Char)
+
+let rec f lexbuf =
+	match Lex.token lexbuf with
+	| Eof -> []
+	| Str s -> s :: f lexbuf
+
+let setify s = String.fold_right S.add s S.empty
+
+let diff s =
+	let half = String.length s / 2 in
+	let l, r = setify (String.sub s 0 half), setify (String.sub s half half) in
+	S.choose (S.inter l r)
+
+let score c =
+	let (start, offset) = 
+		match c with
+		| 'a'..'z' -> ('a', 0)
+		| 'A'..'Z' -> ('A', 26)
+		| _ -> invalid_arg "score"
+	in
+	Char.code c - Char.code start + 1 + offset
+
+let () =
+	stdin
+		|> Lexing.from_channel
+		|> f
+		|> List.map diff
+		|> List.map score
+		|> List.fold_left (+) 0
+		|> Printf.printf "%d\n"

@@ 0,0 1,36 @@
+open Lex
+
+module S = Set.Make(Char)
+
+let rec f lexbuf =
+	match Lex.token lexbuf with
+	| Eof -> []
+	| Str s -> s :: f lexbuf
+
+let setify s = String.fold_right S.add s S.empty
+
+let rec find_badges = function
+	| [] -> []
+	| a :: b :: c :: l ->
+			let a, b, c = setify a, setify b, setify c in
+			let d = S.inter (S.inter a b) c in
+			S.choose d :: find_badges l
+	| _ -> invalid_arg "find_badges"
+
+let score c =
+	let (start, offset) =
+		match c with
+		| 'a'..'z' -> ('a', 0)
+		| 'A'..'Z' -> ('A', 26)
+		| _ -> invalid_arg "score"
+	in
+	Char.code c - Char.code start + 1 + offset
+
+let () =
+	stdin
+		|> Lexing.from_channel
+		|> f
+		|> find_badges
+		|> List.map score
+		|> List.fold_left (+) 0
+		|> Printf.printf "%d\n"