77 lines
1.6 KiB
Nix
77 lines
1.6 KiB
Nix
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{ pkgs, lib }:
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with lib;
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let
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input = splitString "\n\n" (fileContents ./input.txt);
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getCharOffset = index: 1 + 4 * (index - 1);
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getLineAttrs = line: pipe (range 1 9) [
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(map (n: nameValuePair (toString n) (getCharOffset n)))
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listToAttrs
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(mapAttrs (_: elemAt (stringToCharacters line)))
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(filterAttrs (_: char: char != " "))
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];
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stack = pipe input [
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(flip elemAt 0)
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(splitString "\n")
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# remove the line with stack indices
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reverseList
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(drop 1)
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reverseList
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(map getLineAttrs)
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zipAttrs
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];
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moves = pipe input [
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(flip elemAt 1)
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(splitString "\n")
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(map (s:
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let words = splitString " " s;
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in {
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amount = elemAt words 1;
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from = elemAt words 3;
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to = elemAt words 5;
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}
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))
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(map (mapAttrs (_: toInt)))
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];
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executeStackMove = move: stack:
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stack // {
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${toString move.from} = drop move.amount stack.${toString move.from};
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${toString move.to} = (reverseList (take move.amount stack.${toString move.from})) ++ stack.${toString move.to};
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};
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answer1 = pipe stack
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((map executeStackMove moves)
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++ [
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(mapAttrsToList (_: head))
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concatStrings
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]);
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executeStackMove2 = move: stack:
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stack // {
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${toString move.from} = drop move.amount stack.${toString move.from};
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${toString move.to} = (take move.amount stack.${toString move.from}) ++ stack.${toString move.to};
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};
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answer2 = pipe stack
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((map executeStackMove2 moves)
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++ [
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(mapAttrsToList (_: head))
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concatStrings
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]);
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in pkgs.writeText "answers" ''
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Task1:
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${answer1}
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Task2:
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${answer2}
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''
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