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18 lines
627 B
JavaScript
18 lines
627 B
JavaScript
const findConvexHull = async (pts) => {
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const _ = (await import('https://cdn.jsdelivr.net/npm/lodash@4.17.21/+esm')).default;
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const u = _.uniqWith(pts, _.isEqual);
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if (u.length < 3) return u;
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const s = _.sortBy(u, ['x', 'y']);
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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 b = (list, h = []) => {
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for (const p of list) {
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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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}
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return h;
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};
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const l = b(s);
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const r = b(s.reverse());
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return l.slice(0, -1).concat(r.slice(0, -1));
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};
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export default findConvexHull; |