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20 lines
589 B
JavaScript
20 lines
589 B
JavaScript
export async function findConvexHull(a){
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const _ = (await import('https://cdn.jsdelivr.net/npm/lodash-es@4.17.21/lodash.min.js')).default
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a = _.uniqWith(a,_.isEqual)
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a = _.sortBy(a,['x','y'])
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const c=(o,p,q)=>((p.x-o.x)*(q.y-o.y)-(p.y-o.y)*(q.x-o.x))
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const b=[]
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for(const p of a){
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while(b.length>1 && c(b[b.length-2],b[b.length-1],p)<=0) b.pop()
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b.push(p)
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}
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const u=[]
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for(const p of [...a].reverse()){
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while(u.length>1 && c(u[u.length-2],u[u.length-1],p)<=0) u.pop()
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u.push(p)
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}
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u.pop()
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b.pop()
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return [...b,...u]
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}
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export default findConvexHull; |