13 lines
592 B
Nix
13 lines
592 B
Nix
{ lib, utils, ... }:
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with lib;
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with builtins;
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with utils;
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let
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records = map (l: map toInt (splitWhitespace l)) (readLines ./input);
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getMaxDelta = l: (foldl' (prev: value: { inherit value; maxDelta = max prev.maxDelta (delta prev.value value); } ) { value = head l; maxDelta = 0; } l).maxDelta;
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isSafe = r: let sorted = sort lessThan r; in (r == sorted || r == (reverseList sorted)) && allUnique r && (3 >= getMaxDelta r);
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isSafeDampened = r: any isSafe ([ r ] ++ (map (deleteAt r) (range 0 (length r))));
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in {
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part1 = count isSafe records;
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part2 = count isSafeDampened records;
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}
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