37 lines
930 B
Nix
37 lines
930 B
Nix
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{ 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:
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let s = reSplit ": " l;
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in {
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target = toInt (head s);
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candidates = map toInt (splitWhitespace (last s));
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}) (readLines ./input);
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concatInts = x: y: toIntBase10 "${toString x}${toString y}";
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canProduce' = current: target: candidates: ops:
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if current > target then
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false
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else if candidates == [ ] then
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current == target
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else
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any (op:
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canProduce' (op current (head candidates)) target (tail candidates) ops)
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ops;
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canProduce = operators: r:
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if r.candidates == [ ] then
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r.target == 0
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else
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canProduce' (head r.candidates) r.target (tail r.candidates) operators;
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in {
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part1 =
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listSumWith (getAttr "target") (filter (canProduce [ add mul ]) records);
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part2 = listSumWith (getAttr "target")
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(filter (canProduce [ add mul concatInts ]) records);
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}
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