P87 · Packing and covering · Classic · Easy

Equal discs covering a disc · n = 35

Cover the largest possible disc with n unit-radius discs. Maximise the covered disc radius.

Instancen = 35
ObjectiveMaximize covered disc radius

Record comparison

covered disc radius · Higher is better
RecordValue / intervalAuthor / holderSource
External best known——No reference listed
Site recordNo player record yet——

Formal definition

  • ContainerThe editor and certificate normalize to the closed unit disc centred at (1,1). This is a coordinate convention only; scores use the literature's unit-piece scale. Boundary contact is allowed.
  • SubmissionSubmit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.
  • ConstraintsThe n distinct centres lie in the target disc. Covering discs may overlap and protrude, but must cover every target point.
  • PrecisionInput decimals are exact rationals; regular-polygon vertices are algebraic, not rounded templates. Feasibility has no floating-point tolerance. A finite-decimal certificate is not a continuous optimality proof.
  • ObjectiveCovered disc radius R = 1/r, larger is better.
Open the full editor ↗

Layout shown: starter layout

VERIFIED CONSTRUCTIONVERIFIED CONSTRUCTION

Getting a feel for it

Source and certificate

External targets are converted with their printed precision; decimal coordinate certificates are separate. Reconstruction loss never lowers the literature target, and a source construction is not automatically an optimality proof.

Source
The current arrangement for Equal discs covering a disc n = 35
LAYOUT & HISTORY

Starter layout

Inspect the layout, solver notes and record history.

Challenge this record ↗Submit a proof / idea ↓Share a proof or idea in the discussion. Accepted contributions can earn proof points.
ANSWER FORMAT

How to write your answer

the closed unit disc centred at (1,1)

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4.

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.915619200",
      "y": "0.941901461"
    },
    {
      "turn": "0",
      "x": "1.278042032",
      "y": "0.981719571"
    },
    {
      "turn": "0",
      "x": "1.100567874",
      "y": "1.251167255"
    },
    {
      "turn": "0",
      "x": "1.107969289",
      "y": "0.677518743"
    },
    {
      "turn": "0",
      "x": "0.760028992",
      "y": "1.235383383"
    },
    {
      "turn": "0",
      "x": "0.736861226",
      "y": "0.643892148"
    },
    {
      "turn": "0",
      "x": "0.557236326",
      "y": "0.938917226"
    },
    {
      "turn": "0",
      "x": "1.467094761",
      "y": "1.284077905"
    },
    {
      "turn": "0",
      "x": "1.474223822",
      "y": "0.713332895"
    },
    {
      "turn": "0",
      "x": "0.938172499",
      "y": "1.554186458"
    },
    {
      "turn": "0",
      "x": "0.929467518",
      "y": "0.382588076"
    },
    {
      "turn": "0",
      "x": "1.644548775",
      "y": "1.014464012"
    },
    {
      "turn": "0",
      "x": "1.289460909",
      "y": "1.553063765"
    },
    {
      "turn": "0",
      "x": "1.303748589",
      "y": "0.418460905"
    },
    {
      "turn": "0",
      "x": "0.415456886",
      "y": "1.225597247"
    },
    {
      "turn": "0",
      "x": "0.433707251",
      "y": "0.652158397"
    },
    {
      "turn": "0",
      "x": "0.614476252",
      "y": "1.536630139"
    },
    {
      "turn": "0",
      "x": "0.580495856",
      "y": "0.311592406"
    },
    {
      "turn": "0",
      "x": "0.195097057",
      "y": "0.934877532"
    },
    {
      "turn": "0",
      "x": "1.830656432",
      "y": "1.321790382"
    },
    {
      "turn": "0",
      "x": "1.803021281",
      "y": "0.678632735"
    },
    {
      "turn": "0",
      "x": "1.658640169",
      "y": "1.581891844"
    },
    {
      "turn": "0",
      "x": "1.664114627",
      "y": "0.419275453"
    },
    {
      "turn": "0",
      "x": "1.095808633",
      "y": "1.855635984"
    },
    {
      "turn": "0",
      "x": "1.085034226",
      "y": "0.127098249"
    },
    {
      "turn": "0",
      "x": "0.799884332",
      "y": "1.866426919"
    },
    {
      "turn": "0",
      "x": "0.730979289",
      "y": "0.059629409"
    },
    {
      "turn": "0",
      "x": "1.968935541",
      "y": "0.985679480"
    },
    {
      "turn": "0",
      "x": "0.252220119",
      "y": "1.486372670"
    },
    {
      "turn": "0",
      "x": "0.304063062",
      "y": "0.343895288"
    },
    {
      "turn": "0",
      "x": "0.047513294",
      "y": "1.184989740"
    },
    {
      "turn": "0",
      "x": "0.108985782",
      "y": "0.672747762"
    },
    {
      "turn": "0",
      "x": "1.433149263",
      "y": "1.848311736"
    },
    {
      "turn": "0",
      "x": "1.445777665",
      "y": "0.128714163"
    },
    {
      "turn": "0",
      "x": "0.449069453",
      "y": "1.788666214"
    }
  ],
  "radius": "0.202449536"
}
Submission format and technical detailsOpen this when you are ready to prepare a JSON answer+

Instance parameters

{
  "n": 35,
  "sides": 5
}

Starter answer

{
  "placements": [
    {
      "turn": "0",
      "x": "0.915619200",
      "y": "0.941901461"
    },
    {
      "turn": "0",
      "x": "1.278042032",
      "y": "0.981719571"
    },
    {
      "turn": "0",
      "x": "1.100567874",
      "y": "1.251167255"
    },
    {
      "turn": "0",
      "x": "1.107969289",
      "y": "0.677518743"
    },
    {
      "turn": "0",
      "x": "0.760028992",
      "y": "1.235383383"
    },
    {
      "turn": "0",
      "x": "0.736861226",
      "y": "0.643892148"
    },
    {
      "turn": "0",
      "x": "0.557236326",
      "y": "0.938917226"
    },
    {
      "turn": "0",
      "x": "1.467094761",
      "y": "1.284077905"
    },
    {
      "turn": "0",
      "x": "1.474223822",
      "y": "0.713332895"
    },
    {
      "turn": "0",
      "x": "0.938172499",
      "y": "1.554186458"
    },
    {
      "turn": "0",
      "x": "0.929467518",
      "y": "0.382588076"
    },
    {
      "turn": "0",
      "x": "1.644548775",
      "y": "1.014464012"
    },
    {
      "turn": "0",
      "x": "1.289460909",
      "y": "1.553063765"
    },
    {
      "turn": "0",
      "x": "1.303748589",
      "y": "0.418460905"
    },
    {
      "turn": "0",
      "x": "0.415456886",
      "y": "1.225597247"
    },
    {
      "turn": "0",
      "x": "0.433707251",
      "y": "0.652158397"
    },
    {
      "turn": "0",
      "x": "0.614476252",
      "y": "1.536630139"
    },
    {
      "turn": "0",
      "x": "0.580495856",
      "y": "0.311592406"
    },
    {
      "turn": "0",
      "x": "0.195097057",
      "y": "0.934877532"
    },
    {
      "turn": "0",
      "x": "1.830656432",
      "y": "1.321790382"
    },
    {
      "turn": "0",
      "x": "1.803021281",
      "y": "0.678632735"
    },
    {
      "turn": "0",
      "x": "1.658640169",
      "y": "1.581891844"
    },
    {
      "turn": "0",
      "x": "1.664114627",
      "y": "0.419275453"
    },
    {
      "turn": "0",
      "x": "1.095808633",
      "y": "1.855635984"
    },
    {
      "turn": "0",
      "x": "1.085034226",
      "y": "0.127098249"
    },
    {
      "turn": "0",
      "x": "0.799884332",
      "y": "1.866426919"
    },
    {
      "turn": "0",
      "x": "0.730979289",
      "y": "0.059629409"
    },
    {
      "turn": "0",
      "x": "1.968935541",
      "y": "0.985679480"
    },
    {
      "turn": "0",
      "x": "0.252220119",
      "y": "1.486372670"
    },
    {
      "turn": "0",
      "x": "0.304063062",
      "y": "0.343895288"
    },
    {
      "turn": "0",
      "x": "0.047513294",
      "y": "1.184989740"
    },
    {
      "turn": "0",
      "x": "0.108985782",
      "y": "0.672747762"
    },
    {
      "turn": "0",
      "x": "1.433149263",
      "y": "1.848311736"
    },
    {
      "turn": "0",
      "x": "1.445777665",
      "y": "0.128714163"
    },
    {
      "turn": "0",
      "x": "0.449069453",
      "y": "1.788666214"
    }
  ],
  "radius": "0.202449536"
}

Submit {radius, placements:[{x,y,turn},…]}, with decimal strings of at most nine places. x,y are centres; circles require turn=0, polygons use turn=tan(θ/2). Coordinates and turn lie in ±4; 0 < radius ≤ 4. · Verifier v1.0.0

DISCUSSION

Discussion

Talk strategy, share methods, ask why you are stuck. Every signed-in user can post. Posts carry your public byline, the same name your records use; the #number after it is the account's signup ordinal, so a name cannot be worn by someone else. New posts appear after an automated review.

No threads yet. Be the first to talk about this problem?