52 lines
1.3 KiB
Text
52 lines
1.3 KiB
Text
let input_line_opt ic =
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try Some(input_line ic)
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with End_of_file -> None
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(* load each line in a list *)
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let read_lines ic =
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let rec aux acc =
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match input_line_opt ic with
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| Some line -> aux (line :: acc)
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| None -> (List.rev acc)
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in
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aux []
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let char_list_of_string str =
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let lst = ref [] in
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String.iter (fun c -> lst := c :: !lst) str;
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(List.rev !lst)
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let is_ordered word =
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let rec aux = function
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| c1::c2::tl ->
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if c1 <= c2
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then aux (c2::tl)
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else false
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| c::[] -> true
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| [] -> true (* should only occur with an empty string *)
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in
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aux (char_list_of_string word)
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let longest_words words =
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let res, _ =
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List.fold_left
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(fun (lst, n) word ->
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let len = String.length word in
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let comp = compare len n in
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match lst, comp with
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| lst, 0 -> ((word::lst), n) (* len = n *)
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| lst, -1 -> (lst, n) (* len < n *)
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| _, 1 -> ([word], len) (* len > n *)
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| _ -> assert false
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)
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([""], 0) words
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in
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(List.rev res)
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let () =
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let ic = open_in "unixdict.txt" in
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let words = read_lines ic in
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let lower_words = List.map String.lowercase words in
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let ordered_words = List.filter is_ordered lower_words in
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let longest_ordered_words = longest_words ordered_words in
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List.iter print_endline longest_ordered_words
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