43 lines
1003 B
OCaml
43 lines
1003 B
OCaml
type map = string array
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let (.%[]) str i = str.[i mod String.length str]
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let (+=) r x = r := !r + x
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let iter_map ?(step_x=1) ?(step_y=1) f arr =
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let i = ref 0 in let j = ref 0 in
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while !i < Array.length arr do
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f arr.(!i).%[!j];
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i += step_x; j += step_y
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done
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let read_file = Bracket.infile_lines ~line:Fun.id ~of_seq:Array.of_seq
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let count_trees ?step_x ?step_y map =
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let count = ref 0 in
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iter_map ?step_x ?step_y (fun c -> if c = '#' then incr count) map;
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!count
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let main1 input =
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Format.printf "%d\n" (count_trees ~step_y:3 (read_file input))
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let main2 input =
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let map = read_file input in
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Misc.print_prod
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[count_trees map;
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count_trees map ~step_y:3;
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count_trees map ~step_y:5;
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count_trees map ~step_y:7;
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count_trees map ~step_x:2]
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let main = Misc.main 3 [|main1; main2|]
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let%expect_test _ =
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main1 "../../data/day3";
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[%expect{| 244 |}]
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let%expect_test _ =
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main2 "../../data/day3";
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[%expect{| 90 * 244 * 97 * 92 * 48 = 9406609920 |}]
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