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 = 42

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 = 42
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42 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 = 42 的当前纪录构型,161.887091638703899028
当前第一名

161.887091638703899028

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": [
    [
      "10.542349166",
      "14.312012839"
    ],
    [
      "11.542349167",
      "12.579962030"
    ],
    [
      "9.448663025",
      "12.637542585"
    ],
    [
      "9.453860554",
      "10.637549336"
    ],
    [
      "11.453087722",
      "10.581954922"
    ],
    [
      "7.620432811",
      "9.838460656"
    ],
    [
      "13.228043356",
      "9.660254048"
    ],
    [
      "10.453087721",
      "8.849904113"
    ],
    [
      "6.526746670",
      "8.163990401"
    ],
    [
      "8.600913000",
      "8.095285791"
    ],
    [
      "12.228043355",
      "7.928203238"
    ],
    [
      "14.228043357",
      "7.928203238"
    ],
    [
      "5.233263033",
      "6.183623462"
    ],
    [
      "7.230333453",
      "6.291835053"
    ],
    [
      "9.228043352",
      "6.196152429"
    ],
    [
      "11.228043354",
      "6.196152429"
    ],
    [
      "13.228043356",
      "6.196152429"
    ],
    [
      "15.228043358",
      "6.196152429"
    ],
    [
      "8.141371676",
      "4.511345824"
    ],
    [
      "4.089521998",
      "4.432517481"
    ],
    [
      "10.228043353",
      "4.464101620"
    ],
    [
      "12.228043355",
      "4.464101620"
    ],
    [
      "14.228043357",
      "4.464101620"
    ],
    [
      "16.228043359",
      "4.464101620"
    ],
    [
      "6.088717845",
      "4.375807909"
    ],
    [
      "2.995835857",
      "2.758047226"
    ],
    [
      "11.228043354",
      "2.732050810"
    ],
    [
      "15.228043358",
      "2.732050810"
    ],
    [
      "17.228043360",
      "2.732050810"
    ],
    [
      "7.228043350",
      "2.732050810"
    ],
    [
      "9.228043352",
      "2.732050810"
    ],
    [
      "13.228043356",
      "2.732050810"
    ],
    [
      "5.088717844",
      "2.643757100"
    ],
    [
      "1.898938180",
      "1.055415442"
    ],
    [
      "3.949392338",
      "1.000000001"
    ],
    [
      "6.228043349",
      "1.000000001"
    ],
    [
      "8.228043351",
      "1.000000001"
    ],
    [
      "10.228043353",
      "1.000000001"
    ],
    [
      "12.228043355",
      "1.000000001"
    ],
    [
      "14.228043357",
      "1.000000001"
    ],
    [
      "16.228043359",
      "1.000000001"
    ],
    [
      "18.228043361",
      "1.000000001"
    ]
  ],
  "triangle": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "19.960094171",
      "0.000000000"
    ],
    [
      "10.594852190",
      "16.221074936"
    ]
  ]
}
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": 42
}

当前第一名的答案

{
  "centers": [
    [
      "10.542349166",
      "14.312012839"
    ],
    [
      "11.542349167",
      "12.579962030"
    ],
    [
      "9.448663025",
      "12.637542585"
    ],
    [
      "9.453860554",
      "10.637549336"
    ],
    [
      "11.453087722",
      "10.581954922"
    ],
    [
      "7.620432811",
      "9.838460656"
    ],
    [
      "13.228043356",
      "9.660254048"
    ],
    [
      "10.453087721",
      "8.849904113"
    ],
    [
      "6.526746670",
      "8.163990401"
    ],
    [
      "8.600913000",
      "8.095285791"
    ],
    [
      "12.228043355",
      "7.928203238"
    ],
    [
      "14.228043357",
      "7.928203238"
    ],
    [
      "5.233263033",
      "6.183623462"
    ],
    [
      "7.230333453",
      "6.291835053"
    ],
    [
      "9.228043352",
      "6.196152429"
    ],
    [
      "11.228043354",
      "6.196152429"
    ],
    [
      "13.228043356",
      "6.196152429"
    ],
    [
      "15.228043358",
      "6.196152429"
    ],
    [
      "8.141371676",
      "4.511345824"
    ],
    [
      "4.089521998",
      "4.432517481"
    ],
    [
      "10.228043353",
      "4.464101620"
    ],
    [
      "12.228043355",
      "4.464101620"
    ],
    [
      "14.228043357",
      "4.464101620"
    ],
    [
      "16.228043359",
      "4.464101620"
    ],
    [
      "6.088717845",
      "4.375807909"
    ],
    [
      "2.995835857",
      "2.758047226"
    ],
    [
      "11.228043354",
      "2.732050810"
    ],
    [
      "15.228043358",
      "2.732050810"
    ],
    [
      "17.228043360",
      "2.732050810"
    ],
    [
      "7.228043350",
      "2.732050810"
    ],
    [
      "9.228043352",
      "2.732050810"
    ],
    [
      "13.228043356",
      "2.732050810"
    ],
    [
      "5.088717844",
      "2.643757100"
    ],
    [
      "1.898938180",
      "1.055415442"
    ],
    [
      "3.949392338",
      "1.000000001"
    ],
    [
      "6.228043349",
      "1.000000001"
    ],
    [
      "8.228043351",
      "1.000000001"
    ],
    [
      "10.228043353",
      "1.000000001"
    ],
    [
      "12.228043355",
      "1.000000001"
    ],
    [
      "14.228043357",
      "1.000000001"
    ],
    [
      "16.228043359",
      "1.000000001"
    ],
    [
      "18.228043361",
      "1.000000001"
    ]
  ],
  "triangle": [
    [
      "0.000000000",
      "0.000000000"
    ],
    [
      "19.960094171",
      "0.000000000"
    ],
    [
      "10.594852190",
      "16.221074936"
    ]
  ]
}

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

讨论区

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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