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13 lines
557 B
JavaScript
13 lines
557 B
JavaScript
const findConvexHull = async (pts) => {
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const { default: _ } = await import('https://cdn.jsdelivr.net/npm/lodash@4.17.21/+esm');
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const s = _.sortBy(_.uniqWith(pts, _.isEqual), ['x', 'y']);
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if (s.length < 3) return s;
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const k = (a, b, c) => (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
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const f = (h, p) => {
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while (h.length > 1 && k(h[h.length - 2], h[h.length - 1], p) <= 0) h.pop();
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h.push(p);
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return h;
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};
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return [...s.reduce(f, []).slice(0, -1), ...s.reduceRight(f, []).slice(0, -1)];
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};
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export default findConvexHull; |