P66 · 装箱与覆盖 · 经典问题 · 难

最小面积三角形内的单位圆装箱 · n = 39

文献中也称circles in arbitrary trianglesunit circles in a minimum-area trianglecircle packing in a triangle of variable shape

在任意三角形中放置 n 个半径为 1、内部互不重叠的圆;三角形的三个顶点也是答案的一部分。让这个三角形的面积尽可能小。

子题n = 39
目标最小化 三角形面积

严格定义

  • 容器容器是形状不预先固定的非退化三角形;三个顶点和所有圆心都位于 0 到 200 的坐标框内
  • 提交三个按逆时针顺序排列的三角形顶点,以及恰好 n 个圆心
  • 每个圆的半径固定为 1;圆的内部两两不相交,相切允许
  • 容纳每个圆都完整落在三角形内,可以与边相切
  • 目标让三角形面积尽可能小
挑战这个纪录
已验证构造39 个半径为 1 的圆

帮助理解

容器也是变量

普通装箱只移动圆;这里连三条边的方向都能改变。一条边转动一点,可能同时释放多个接触,也可能让整套构形失稳。

难点是接触结构

候选最优解通常由圆—圆、圆—边相切关系卡死。真正的搜索不是把圆平均铺开,而是在大量可能的接触图之间找到对的那一张。

从非平凡实例开始

Friedman 的公开表给出了 n≤50 的当前最好已知构形。n=1、2 已证明,n=3 仍是简单的等边三角形排布,因此本站从 n=4 开放;匹配公开构形只是到达前沿,打破它们才是新纪录。

查看来源
最小面积三角形内的单位圆装箱 n = 39 的当前纪录构型,151.83073130385406932
当前第一名

151.83073130385406932

三角形面积

已追平已知最好
答案来源Tej Stead
解题方式公开参考构造
挑战这个纪录
ANSWER FORMAT

答案怎么写

坐标单位就是圆的半径:每个圆半径固定为 1。三个顶点和所有圆心都写在 0≤x,y≤200 的坐标框内,顶点必须逆时针排列。

提交按逆时针排列的三个顶点 triangle,以及恰好 n 个圆心 centers。圆的半径固定为 1;所有数写成最多九位小数的字符串。

当前第一名的答案

{
  "centers": [
    [
      "10.003904230",
      "15.056574842"
    ],
    [
      "8.886981509",
      "13.392703456"
    ],
    [
      "10.878519520",
      "13.208919553"
    ],
    [
      "9.723588986",
      "11.576088994"
    ],
    [
      "7.732050974",
      "11.392305091"
    ],
    [
      "11.684352136",
      "11.181870731"
    ],
    [
      "6.732050953",
      "9.660254246"
    ],
    [
      "8.851625356",
      "9.726770584"
    ],
    [
      "11.250887941",
      "9.229408448"
    ],
    [
      "12.906553448",
      "8.107458404"
    ],
    [
      "5.732050931",
      "7.928203401"
    ],
    [
      "7.732050974",
      "7.928203401"
    ],
    [
      "9.732051018",
      "7.928203401"
    ],
    [
      "10.802998665",
      "6.239099666"
    ],
    [
      "4.732050910",
      "6.196152556"
    ],
    [
      "8.732050996",
      "6.196152556"
    ],
    [
      "6.732050953",
      "6.196152556"
    ],
    [
      "12.871511437",
      "6.107765370"
    ],
    [
      "14.269927879",
      "4.677929146"
    ],
    [
      "5.732050931",
      "4.464101712"
    ],
    [
      "9.732051018",
      "4.464101712"
    ],
    [
      "3.732050888",
      "4.464101712"
    ],
    [
      "7.732050974",
      "4.464101712"
    ],
    [
      "11.732051061",
      "4.464101712"
    ],
    [
      "2.732050867",
      "2.732050867"
    ],
    [
      "4.732050910",
      "2.732050867"
    ],
    [
      "6.732050953",
      "2.732050867"
    ],
    [
      "8.732050996",
      "2.732050867"
    ],
    [
      "10.732051039",
      "2.732050867"
    ],
    [
      "12.732051082",
      "2.732050867"
    ],
    [
      "14.732051126",
      "2.732050867"
    ],
    [
      "1.732050845",
      "1.000000022"
    ],
    [
      "3.732050888",
      "1.000000022"
    ],
    [
      "5.732050931",
      "1.000000022"
    ],
    [
      "7.732050974",
      "1.000000022"
    ],
    [
      "9.732051018",
      "1.000000022"
    ],
    [
      "11.732051061",
      "1.000000022"
    ],
    [
      "13.732051104",
      "1.000000022"
    ],
    [
      "15.732051147",
      "1.000000022"
    ]
  ],
  "triangle": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "17.205712692",
      "0.000000000"
    ],
    [
      "10.189582397",
      "17.648874420"
    ]
  ]
}
提交格式与技术细节需要编写程序或准备 JSON 答案时再查看

子题参数

{
  "n": 39
}

当前第一名的答案

{
  "centers": [
    [
      "10.003904230",
      "15.056574842"
    ],
    [
      "8.886981509",
      "13.392703456"
    ],
    [
      "10.878519520",
      "13.208919553"
    ],
    [
      "9.723588986",
      "11.576088994"
    ],
    [
      "7.732050974",
      "11.392305091"
    ],
    [
      "11.684352136",
      "11.181870731"
    ],
    [
      "6.732050953",
      "9.660254246"
    ],
    [
      "8.851625356",
      "9.726770584"
    ],
    [
      "11.250887941",
      "9.229408448"
    ],
    [
      "12.906553448",
      "8.107458404"
    ],
    [
      "5.732050931",
      "7.928203401"
    ],
    [
      "7.732050974",
      "7.928203401"
    ],
    [
      "9.732051018",
      "7.928203401"
    ],
    [
      "10.802998665",
      "6.239099666"
    ],
    [
      "4.732050910",
      "6.196152556"
    ],
    [
      "8.732050996",
      "6.196152556"
    ],
    [
      "6.732050953",
      "6.196152556"
    ],
    [
      "12.871511437",
      "6.107765370"
    ],
    [
      "14.269927879",
      "4.677929146"
    ],
    [
      "5.732050931",
      "4.464101712"
    ],
    [
      "9.732051018",
      "4.464101712"
    ],
    [
      "3.732050888",
      "4.464101712"
    ],
    [
      "7.732050974",
      "4.464101712"
    ],
    [
      "11.732051061",
      "4.464101712"
    ],
    [
      "2.732050867",
      "2.732050867"
    ],
    [
      "4.732050910",
      "2.732050867"
    ],
    [
      "6.732050953",
      "2.732050867"
    ],
    [
      "8.732050996",
      "2.732050867"
    ],
    [
      "10.732051039",
      "2.732050867"
    ],
    [
      "12.732051082",
      "2.732050867"
    ],
    [
      "14.732051126",
      "2.732050867"
    ],
    [
      "1.732050845",
      "1.000000022"
    ],
    [
      "3.732050888",
      "1.000000022"
    ],
    [
      "5.732050931",
      "1.000000022"
    ],
    [
      "7.732050974",
      "1.000000022"
    ],
    [
      "9.732051018",
      "1.000000022"
    ],
    [
      "11.732051061",
      "1.000000022"
    ],
    [
      "13.732051104",
      "1.000000022"
    ],
    [
      "15.732051147",
      "1.000000022"
    ]
  ],
  "triangle": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "17.205712692",
      "0.000000000"
    ],
    [
      "10.189582397",
      "17.648874420"
    ]
  ]
}

提交按逆时针排列的三个顶点 triangle,以及恰好 n 个圆心 centers。圆的半径固定为 1;所有数写成最多九位小数的字符串。 · 验证器 v1.0.0

DISCUSSION

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聊思路、贴方法、问为什么卡住。发帖即公开署名,与纪录同一个名字;署名后的 #编号是账号的注册序号,冒不了名。发言资格与实绩绑定:破过一次纪录,就永久拥有发言权。新发言经自动审核后公开。

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