81 lines
2.0 KiB
JavaScript
81 lines
2.0 KiB
JavaScript
(() => {
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'use strict';
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// main :: IO ()
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const main = () => {
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const
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size = n => enumFromTo(0)(
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quot(100, n)
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),
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nuggets = new Set(
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size(6).flatMap(
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x => size(9).flatMap(
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y => size(20).flatMap(
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z => {
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const v = sum([6 * x, 9 * y, 20 * z]);
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return 101 > v ? (
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[v]
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) : [];
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}
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),
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)
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)
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),
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xs = dropWhile(
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x => nuggets.has(x),
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enumFromThenTo(100, 99, 1)
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);
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return 0 < xs.length ? (
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xs[0]
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) : 'No unreachable quantities found in this range';
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};
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// GENERIC FUNCTIONS ----------------------------------
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// dropWhile :: (a -> Bool) -> [a] -> [a]
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const dropWhile = (p, xs) => {
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const lng = xs.length;
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return 0 < lng ? xs.slice(
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until(
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i => i === lng || !p(xs[i]),
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i => 1 + i,
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0
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)
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) : [];
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};
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// enumFromThenTo :: Int -> Int -> Int -> [Int]
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const enumFromThenTo = (x1, x2, y) => {
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const d = x2 - x1;
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return Array.from({
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length: Math.floor(y - x2) / d + 2
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}, (_, i) => x1 + (d * i));
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};
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// ft :: Int -> Int -> [Int]
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const enumFromTo = m => n =>
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Array.from({
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length: 1 + n - m
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}, (_, i) => m + i);
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// quot :: Int -> Int -> Int
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const quot = (n, m) => Math.floor(n / m);
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// sum :: [Num] -> Num
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const sum = xs => xs.reduce((a, x) => a + x, 0);
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// until :: (a -> Bool) -> (a -> a) -> a -> a
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const until = (p, f, x) => {
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let v = x;
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while (!p(v)) v = f(v);
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return v;
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};
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// MAIN ---
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return console.log(
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main()
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);
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})();
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