73 lines
1.6 KiB
Nix
73 lines
1.6 KiB
Nix
{ pkgs, lib }:
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with lib;
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let
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input = pipe (fileContents ./input.txt) [
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(splitString "\n")
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];
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answer1 = pipe input [
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(map stringToCharacters)
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(x: {
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forwards = x;
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reverse = map reverseList x;
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})
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(mapAttrs (_: map (findFirst (x: builtins.match "[[:digit:]]" x == [ ]) null)))
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({ forwards, reverse }: zipListsWith (a: b: a + b) forwards reverse)
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(map toInt)
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(foldr (a: b: a + b) 0)
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toString
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];
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letterNumbers = {
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"one" = "1";
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"two" = "2";
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"three" = "3";
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"four" = "4";
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"five" = "5";
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"six" = "6";
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"seven" = "7";
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"eight" = "8";
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"nine" = "9";
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};
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reverseString = s: pipe s [
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stringToCharacters
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reverseList
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(builtins.concatStringsSep "")
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];
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# NOTE: builtins.match somehow always matches the last group first.
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# I believe it might be an implementation detail.
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answer2 = pipe input [
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(x: {
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last = pipe x [
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(map (builtins.match "^.*([[:digit:]]|${builtins.concatStringsSep "|" (builtins.attrNames letterNumbers)}).*$"))
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(map head)
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];
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first = pipe x [
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(map reverseString)
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(let
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rLetterNumbers = map reverseString (builtins.attrNames letterNumbers);
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in map (builtins.match "^.*([[:digit:]]|${builtins.concatStringsSep "|" rLetterNumbers}).*$"))
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(map head)
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(map reverseString)
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];
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})
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(mapAttrs (_: map (x: letterNumbers.${x} or x)))
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({ first, last }: zipListsWith (a: b: a + b) first last)
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(map toInt)
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(foldr (a: b: a + b) 0)
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toString
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];
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in
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pkgs.writeText "answers" ''
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Task1:
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${answer1}
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Task2:
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${answer2}
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''
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