41 lines
801 B
JavaScript
41 lines
801 B
JavaScript
import * as R from "remeda";
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import Victor from "@a-robu/victor";
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import { outOfBound } from "./part1";
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const V = (...args) => new Victor(...args);
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function visibility(forest, x, y, dx, dy) {
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const pos = V(x, y);
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const inc = V(dx, dy);
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let vis = 0;
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while (true) {
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pos.add(inc);
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if (outOfBound(forest.length)(pos)) return vis;
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if (forest[x][y] <= forest[pos.x][pos.y]) return 1 + vis;
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vis++;
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}
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}
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const visibilityAround = (forest) => (x, y) =>
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[
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[0, 1],
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[0, -1],
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[1, 0],
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[-1, 0],
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]
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.map((d) => visibility(forest, x, y, ...d))
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.reduce((a, b) => a * b);
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export default R.createPipe(
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(forest) => {
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const va = visibilityAround(forest);
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return forest.map((l, x) => l.map((_, y) => va(x, y)));
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},
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R.flatten,
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R.maxBy(R.identity)
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);
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