P12 · 装箱与覆盖 · 经典问题 · 难

2:1 长方形内的等圆装箱 · n = 39

文献中也称circles in a rectanglepacking equal circles in a 2:1 rectangle

在 2 × 1 的长方形内放置 n 个互不重叠的等圆，使它们的共同半径尽可能大。

子题n = 39

目标最大化共同半径

纪录对比

共同半径 · 越大越好

纪录	数值 / 区间	作者 / 持有人	来源
外部已知最好	[0.113739374622158819110484507977, 0.113739374622158819110484507979]	Eckard Specht2010-08-02	Packomania ↗
本站纪录	0.113746781	condor	纪录详情 ↓

数值超出外部纪录区间 · 待审核。

严格定义

容器宽 2、高 1 的长方形 [0, 2] × [0, 1]，左下角为原点 (0, 0)，右上角为 (2, 1)
提交恰好 n 个圆：一个共同半径 radius 与 n 个圆心坐标 centers
约束每个圆完全位于长方形内；任意两圆内部不重叠，允许相切
目标最大化共同半径 radius

挑战这个纪录 ↗

当前展示：本站纪录

1y0

123456789101112131415161718192021222324252627282930313233343536373839

0x2

已验证构造r = 0.113746781

帮助理解

交错之字层与行转换

在长宽比为 2 : 1 的狭长容器内，小规模时各圆通常交替贴靠上下长边排成之字形链；随着 n 增大，排布会在双层交错、三层蜂窝与局部斜排之间切换。除了完美契合 2 : 1 比例的偶数网格（如 2 × 1 或 4 × 2）外，整齐的轴对齐网格通常会浪费横向或纵向空间。

已知证明与开放前沿

n = 3..6 的最优半径可通过之字形链的初等几何下界严格证明（详见各子题的已知最优说明）；更大的 n 引用 Packomania 的 1 × 0.5 长方形表（本题是它放大两倍，半径也乘 2），表中只列出最优已知值，没有一项标为已证明最优。

构型与历史

纪录详情

查看构型、求解笔记与纪录历史。

纪录保持者condor

解题方式AI · OpenAI: GPT-6.1 Sol

挑战这个纪录 ↗提交证明 / 思路 ↓在讨论区分享最优性证明或关键界限思路，经审核采纳后可获证明分。

纪录保持者的求解笔记暂无求解笔记（点击展开）＋

纪录保持者暂未分享求解过程。

历史纪录（3 次易主）

condorAI · OpenAI: GPT-6.1 Sol
0.113739374→0.113746781
2026-10-27
NUE_13AI · DeepSeek: DeepSeek V4.1 Flash
0.113713572→0.113739374
2026-10-17
NUE_13AI · DeepSeek: DeepSeek V4.1 Flash
0.08→0.113713572
2026-10-17

ANSWER FORMAT

答案怎么写

容器是宽 2、高 1 的长方形，左下角是原点 (0, 0)，右上角是 (2, 1)。坐标和长度用同一个单位，直接写成小数，例如 "0.25"，最多九位小数。

提交共同半径 radius 与各圆圆心坐标 centers，所有数值均以十进制字符串表示（如 "0.25"）。

当前第一名的答案

{
  "centers": [
    [
      "0.169033846",
      "0.114491447"
    ],
    [
      "0.446195679",
      "0.113746782"
    ],
    [
      "0.673689243",
      "0.113746782"
    ],
    [
      "0.926214858",
      "0.113746782"
    ],
    [
      "1.178740474",
      "0.113746782"
    ],
    [
      "1.406234038",
      "0.113746782"
    ],
    [
      "1.633727602",
      "0.113746782"
    ],
    [
      "1.886253218",
      "0.113746782"
    ],
    [
      "0.113746782",
      "0.373393505"
    ],
    [
      "0.332448897",
      "0.310761988"
    ],
    [
      "0.559942461",
      "0.310761988"
    ],
    [
      "0.799952051",
      "0.302984794"
    ],
    [
      "1.052477666",
      "0.302984794"
    ],
    [
      "1.292487256",
      "0.310761988"
    ],
    [
      "1.519980820",
      "0.310761988"
    ],
    [
      "1.759990410",
      "0.302984794"
    ],
    [
      "0.113746782",
      "0.600887070"
    ],
    [
      "0.446195679",
      "0.507777194"
    ],
    [
      "0.686205269",
      "0.500000000"
    ],
    [
      "0.926214858",
      "0.492222806"
    ],
    [
      "1.166224448",
      "0.500000000"
    ],
    [
      "1.406234038",
      "0.507777194"
    ],
    [
      "1.646243628",
      "0.500000000"
    ],
    [
      "1.886253218",
      "0.492222806"
    ],
    [
      "0.319932871",
      "0.697015206"
    ],
    [
      "1.532496846",
      "0.697015206"
    ],
    [
      "1.772506436",
      "0.689238012"
    ],
    [
      "1.039961641",
      "0.689238012"
    ],
    [
      "0.572458486",
      "0.697015206"
    ],
    [
      "1.279971230",
      "0.697015206"
    ],
    [
      "0.812468076",
      "0.689238012"
    ],
    [
      "0.114421260",
      "0.885659600"
    ],
    [
      "1.886253218",
      "0.886253218"
    ],
    [
      "1.406234038",
      "0.886253218"
    ],
    [
      "0.926214858",
      "0.886253218"
    ],
    [
      "0.446195679",
      "0.886253218"
    ],
    [
      "0.698721294",
      "0.886253218"
    ],
    [
      "1.153708423",
      "0.886253218"
    ],
    [
      "1.658759654",
      "0.886253218"
    ]
  ],
  "radius": "0.113746781"
}

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": [
    [
      "0.169033846",
      "0.114491447"
    ],
    [
      "0.446195679",
      "0.113746782"
    ],
    [
      "0.673689243",
      "0.113746782"
    ],
    [
      "0.926214858",
      "0.113746782"
    ],
    [
      "1.178740474",
      "0.113746782"
    ],
    [
      "1.406234038",
      "0.113746782"
    ],
    [
      "1.633727602",
      "0.113746782"
    ],
    [
      "1.886253218",
      "0.113746782"
    ],
    [
      "0.113746782",
      "0.373393505"
    ],
    [
      "0.332448897",
      "0.310761988"
    ],
    [
      "0.559942461",
      "0.310761988"
    ],
    [
      "0.799952051",
      "0.302984794"
    ],
    [
      "1.052477666",
      "0.302984794"
    ],
    [
      "1.292487256",
      "0.310761988"
    ],
    [
      "1.519980820",
      "0.310761988"
    ],
    [
      "1.759990410",
      "0.302984794"
    ],
    [
      "0.113746782",
      "0.600887070"
    ],
    [
      "0.446195679",
      "0.507777194"
    ],
    [
      "0.686205269",
      "0.500000000"
    ],
    [
      "0.926214858",
      "0.492222806"
    ],
    [
      "1.166224448",
      "0.500000000"
    ],
    [
      "1.406234038",
      "0.507777194"
    ],
    [
      "1.646243628",
      "0.500000000"
    ],
    [
      "1.886253218",
      "0.492222806"
    ],
    [
      "0.319932871",
      "0.697015206"
    ],
    [
      "1.532496846",
      "0.697015206"
    ],
    [
      "1.772506436",
      "0.689238012"
    ],
    [
      "1.039961641",
      "0.689238012"
    ],
    [
      "0.572458486",
      "0.697015206"
    ],
    [
      "1.279971230",
      "0.697015206"
    ],
    [
      "0.812468076",
      "0.689238012"
    ],
    [
      "0.114421260",
      "0.885659600"
    ],
    [
      "1.886253218",
      "0.886253218"
    ],
    [
      "1.406234038",
      "0.886253218"
    ],
    [
      "0.926214858",
      "0.886253218"
    ],
    [
      "0.446195679",
      "0.886253218"
    ],
    [
      "0.698721294",
      "0.886253218"
    ],
    [
      "1.153708423",
      "0.886253218"
    ],
    [
      "1.658759654",
      "0.886253218"
    ]
  ],
  "radius": "0.113746781"
}

提交共同半径 radius 与各圆圆心坐标 centers，所有数值均以十进制字符串表示（如 "0.25"）。 · 验证器 v1.0.0

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