56 lines
1.7 KiB
OCaml
56 lines
1.7 KiB
OCaml
#use "lib/file_utils.ml" ;;
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let priority_of_item c =
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(* ASCII lower case is 97-122, upper case is 65-90 *)
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(* Lower case start at 1, upper case at 27 *)
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let code = Char.code c in
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if code > 90
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then code - 96
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else code - 65 + 27
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in
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let sum_of_priorities fn str =
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let chars = List.sort_uniq compare (list_of_chars str) in
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List.fold_left fn 0 chars
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in
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let sum_rucksack_priorities lines =
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let rucksack_priority str =
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let len2 = (String.length str)/2 in
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let comp1 = String.sub str 0 len2 in
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let comp2 = String.sub str len2 len2 in
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let char_priority agg c =
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if String.contains comp2 c
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then (agg + priority_of_item c)
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else agg
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in
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sum_of_priorities char_priority comp1
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in
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List.fold_left (+) 0 (List.map rucksack_priority lines)
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in
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let rec sum_badge_priorities sum lines =
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let common_badge_priority str1 str2 str3 =
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let char_priority agg c =
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if String.contains str2 c && String.contains str3 c
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then (agg + priority_of_item c)
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else agg
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in
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sum_of_priorities char_priority str1
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in
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match lines with
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| [] -> sum
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| hd1 :: tl1 -> match tl1 with
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| [] -> failwith "number of rows must be divisible by 3"
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| hd2 :: tl2 -> match tl2 with
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| [] -> failwith "number of rows must be divisible by 3"
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| hd3 :: tl3 -> sum_badge_priorities (sum + common_badge_priority hd1 hd2 hd3) tl3
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in
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let contents = read_file "inputs/3.txt" in
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let lines = List.filter (fun l -> String.trim l <> "") (String.split_on_char '\n' contents) in
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let sum1 = sum_rucksack_priorities lines in
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let sum2 = sum_badge_priorities 0 lines in
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Printf.printf "Part 1: %d\n" sum1;
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Printf.printf "Part 2: %d\n" sum2
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