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17 lines
675 B
JavaScript
17 lines
675 B
JavaScript
const findConvexHull = async points => {
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const { default: _ } = await import('https://cdn.jsdelivr.net/npm/lodash@4.17.21/+esm')
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const p = _.sortBy(_.uniqWith(points, _.isEqual), ['x', 'y'])
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if (p.length < 3) return p
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const h = [], x = (a, b, c) => (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x)
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for (let i = 0; i < p.length; i++) {
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while (h.length >= 2 && x(h[h.length - 2], h[h.length - 1], p[i]) <= 0) h.pop()
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h.push(p[i])
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}
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for (let i = p.length - 2, t = h.length + 1; i >= 0; i--) {
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while (h.length >= t && x(h[h.length - 2], h[h.length - 1], p[i]) <= 0) h.pop()
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h.push(p[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; |