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18 lines
656 B
JavaScript
18 lines
656 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 h = [], x = (o, a, b) => (a.x - o.x) * (b.y - o.y) - (a.y - o.y) * (b.x - o.x)
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for (const p of s) {
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while (h.length >= 2 && x(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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const t = h.length + 1
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for (let i = s.length - 2; i >= 0; i--) {
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while (h.length >= t && x(h[h.length - 2], h[h.length - 1], s[i]) <= 0) h.pop()
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h.push(s[i])
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}
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h.pop()
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return h
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}
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export default findConvexHull; |