123 lines
2.5 KiB
Nix
123 lines
2.5 KiB
Nix
{lib, ...}: input: rec {
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content = lib.trim input;
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emptyLines = lines: lines
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|> builtins.length
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|> genStrList ""
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;
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genStrList = str: builtins.genList (_: str);
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rotated = input: input
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|> lib.strings.splitString "\n"
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|> map (lib.stringToCharacters)
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|> (lines: builtins.foldl'
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(lib.zipListsWith (a: b: a + b))
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(emptyLines lines)
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lines)
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|> lib.concatStringsSep "\n"
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;
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len = builtins.length (lib.strings.splitString "\n" content);
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diagonal = input: input
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|> lib.strings.splitString "\n"
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|> map (lib.stringToCharacters)
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|> (lines: builtins.foldl'
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({acc, i}: line: {
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acc = lib.zipListsWith (a: b: a + b) acc
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((genStrList " " i) ++ line ++ (genStrList " " (len - i)));
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i = i + 1;
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})
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{
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acc = (emptyLines lines) ++ emptyLines (builtins.elemAt lines 0);
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i = 0;
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}
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lines)
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|> ({acc, ...}: acc)
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|> map lib.trim
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|> lib.concatStringsSep "\n"
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;
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reversed = input: input
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|> lib.strings.splitString "\n"
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|> map reverseString
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|> lib.concatStringsSep "\n"
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;
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reverseString = s: s
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|> lib.stringToCharacters
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|> lib.reverseList
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|> lib.concatStringsSep ""
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;
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search = term: input: input
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|> builtins.split term
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|> builtins.filter lib.isList
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|> builtins.length
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;
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searchForwardAndBack = term: input:
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search term input +
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search (reverseString term) input;
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findXMAS = searchForwardAndBack "XMAS";
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part1result = findXMAS content
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+ findXMAS (diagonal content)
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+ findXMAS (rotated content)
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+ findXMAS (diagonal (reversed content))
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;
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xmasMatcher = let
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xmas = ''
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M.S
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.A.
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M.S'';
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in
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"${xmas}|${rotated xmas}|${reversed xmas}|${rotated (reversed xmas)}";
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isX-MAS = s: s
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|> builtins.match xmasMatcher
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|> lib.isList
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;
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break3s = s: let
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len = builtins.length s - 2;
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in
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builtins.genList (i: lib.sublist i 3 s) len
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;
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break3lines = s: s
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|> lib.splitString "\n"
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|> map lib.stringToCharacters
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|> break3s
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;
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break3x3s = l: l
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|> map break3s
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|> (groups:
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let empty = builtins.elemAt groups 0
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|> builtins.length
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|> genStrList [];
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in builtins.foldl'
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(lib.zipListsWith (a: b: a ++ ["\n"] ++ b))
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empty groups)
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|> map lib.concatStrings
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|> map lib.trim
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;
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break3x3 = s: s
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|> break3lines
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|> map break3x3s
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|> builtins.concatLists
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;
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part2result = content
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|> break3x3
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|> lib.count isX-MAS
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;
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}
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