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19 lines
614 B
JavaScript
19 lines
614 B
JavaScript
const findConvexHull = async (pts) => {
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const { default: _ } = await import('https://esm.sh/lodash');
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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 f = (l) => {
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const h = [];
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for (const p of l) {
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while (h.length >= 2 && 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 = f(s);
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const h = f([...s].reverse());
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return [...l.slice(0, -1), ...h.slice(0, -1)];
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};
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export default findConvexHull; |