41 lines
1.3 KiB
Nix
41 lines
1.3 KiB
Nix
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let
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# Import nixpkgs lib and input file
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inherit ((builtins.getFlake (builtins.toString ./..)).inputs.nixpkgs) lib;
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input = builtins.readFile (builtins.toString ./input.txt);
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# Define functions
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abs = n: if n < 0 then (-n) else n;
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# Do parsing
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parsed = ( # Define function to sort lines into two lists
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lib.lists.foldr
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(cur: acc: {
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first = acc.first ++ [(lib.strings.toIntBase10 (builtins.elemAt cur 0))];
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second = acc.second ++ [(lib.strings.toIntBase10 (builtins.elemAt cur 1))];
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})
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{ first = []; second = []; }
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) ( # Call with input split on newlines and 3 spaces; formatted like [ [ 1 2 ] [ 3 4 ] [ 5 6 ] ]
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lib.lists.forEach
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(lib.strings.splitString "\n" input)
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(e: lib.strings.splitString " " e)
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);
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sorted = {
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first = lib.lists.sort (a: b: a < b) parsed.first;
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second = lib.lists.sort (a: b: a < b) parsed.second;
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};
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reorganized = (
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lib.lists.imap0
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(i: e: [ e (builtins.elemAt sorted.second i) ])
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sorted.first
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);
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output = (
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(
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lib.lists.foldr
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(cur: acc:
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acc + (abs ((builtins.elemAt cur 0) - (builtins.elemAt cur 1)))
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)
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0
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) reorganized
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);
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in output
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