mirror of
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25 lines
951 B
JavaScript
25 lines
951 B
JavaScript
export async function findConvexHull(points) {
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const _ = await import('https://cdn.jsdelivr.net/npm/lodash-es@4.17.21/+esm');
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if (!Array.isArray(points)) points = [];
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const uniq = _.uniqWith(points, (a, b) => a.x === b.x && a.y === b.y);
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const pts = _.sortBy(uniq, p => [p.x, p.y]);
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if (pts.length <= 1) return pts.slice();
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const cross = (o, a, b) => (a.x - o.x) * (b.y - o.y) - (a.y - o.y) * (b.x - o.x);
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const lower = [];
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for (const p of pts) {
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while (lower.length > 1 && cross(lower[lower.length - 2], lower[lower.length - 1], p) <= 0) lower.pop();
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lower.push(p);
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}
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const upper = [];
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for (let i = pts.length - 1; i >= 0; i--) {
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const p = pts[i];
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while (upper.length > 1 && cross(upper[upper.length - 2], upper[upper.length - 1], p) <= 0) upper.pop();
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upper.push(p);
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}
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upper.pop();
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lower.pop();
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return lower.concat(upper);
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}
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export default findConvexHull;
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// Generation time: 14.502s
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// Result: PASS
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