最省刻度尺设计的组合差集递推算法
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A recursive algorithm of combinatorial difference set design for least scale number on ruler
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收稿日期: 2022-07-04 修回日期: 2023-03-16 接受日期: 2023-03-23
基金资助: |
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Received: 2022-07-04 Revised: 2023-03-16 Accepted: 2023-03-23
作者简介 About authors
唐保祥(1961—),ORCID:https://orcid.org/0000-0002-1631-1482,男,本科,教授,主要从事图论与组合数学研究,E-mail:
关键词:
Keywords:
本文引用格式
唐保祥, 任韩.
TANG Baoxiang, REN Han.
0 引 言
设
1 研究方法
根据极小优美图的定义,一把有
例如,长度为9个单位的直尺,最少刻度数为5(含2个端点),5个刻度的直尺共有4种,如图1所示,其度量方式有8种:
图1
图1
长度为9的最省刻度尺的4种刻度
Fig1
4 different scale values for the ruler with least number of scales with a length of 9
(a) 0,1|0,2|6,9|2,6|1,6|0,6|2,9|1,9|0,9|;
(b) 0,1|7,9|1,4|0,4|4,9|1,7|0,7|1,9|0,9|;
(c) 0,1|7,9|4,7|0,4|4,9|1,7|0,7|1,9|0,9|;
(d) 1,2|0,2|6,9|2,6|1,6|0,6|2,9|1,9|0,9|;
(e) 7,8|7,9|0,3|3,7|3,8|3,9|0,7|0,8|0,9|;
(f) 8,9|0,2|2,5|5,9|0,5|2,8|2,9|0,8|0,9|;
(g) 8,9|0,2|5,8|5,9|0,5|2,8|2,9|0,8|0,9|;
(h) 8,9|7,9|0,3|3,7|3,8|3,9|0,7|0,8|0,9|。
8种度量方式对应的有5个顶点、9条边的8个极小优美图如图2所示。
图2
2 优美标号算法
设简单图
2.1 算法流程
算法完成后,得到
2.2 算法实例
例如,有3条边的优美图,优美标号生成过程如下:
(1)
(2) 因为
(3) 因为
(4) 因为
(5) 因为
(6) 因为
采用优美标号算法,得到有
3 组合差集递推算法
3.1 模型的建立
有
表1 集合{0,1,2,…,n}的所有二元子集
Table 1
(0,1) | (1,2) | (2,3) | (3,4) | … | ( n-1,n ) |
---|---|---|---|---|---|
(0,2) | (1,3) | (2,4) | … | (n-2,n) | |
(0,3) | (1,4) | … | (n-3,n) | ||
… | … | … | |||
(0,n-1) | (1,n) | ||||
(0,n ) |
表1的每行恰取一数对
于是,求有
3.2 求解理论
3.3 递推算法
显然,长度为
易知,二元子集
对每个一元子集
因为长度为
将上述方法一般化,即已知长度为
3.4 算法流程
如果3个步骤执行完毕,仍没有得到长度为
4 计算结果
用组合差集递推算法,得到了长度为
例如,长度为
(1) 0,2,8,10,17,19,30,31,34,35;
(2) 0,2,5,8,11,14,18,33,34,35;
(3) 0,2,5,7,13,19,25,31,34,35;
(4) 0,1,5,12,19,26,29,32,34,35;
(5) 0,1,5,12,16,26,29,32,34,35;
(6) 0,1,4,10,16,22,28,30,33,35;
(7) 0,1,4,5,16,18,25,27,33,35;
(8) 0,1,3,6,9,19,23,30,34,35;
(9) 0,1,3,6,9,16,23,30,34,35;
(10) 0,1,2,17,21,24,27,30,33,35。
采用组合差集递推算法,得到长度为
表2 长度为3~40的最省刻度尺的最省刻度
Table 2
长度 | 其中的一组最省刻度 | 每组 中的 刻度数 | 所有不同的刻度组数 | 长度 | 其中的一组最省刻度 | 每组 中的 刻度数 | 所有不同的刻度组数 |
---|---|---|---|---|---|---|---|
3 | 0,2,3 | 3 | 2 | 22 | 0,4,9,14,19,20,21,22 | 8 | 18 |
4 | 0,2,3,4 | 4 | 3 | 23 | 0,2,5,8,12,21,22,23 | 8 | 4 |
5 | 0,3,4,5 | 4 | 4 | 24 | 0,6,12,19,20,21,22,23,24 | 9 | 944 |
6 | 0,2,5,6 | 4 | 2 | 25 | 0,6,13,20,21,22,23,24,25 | 9 | 460 |
7 | 0,4,5,6,7 | 5 | 12 | 26 | 0,5,11,16,22,23,24,25,26 | 9 | 166 |
8 | 0,3,6,7,8 | 5 | 8 | 27 | 0,5,11,17,23,24,25,26,27 | 9 | 56 |
9 | 0,3,7,8,9 | 5 | 4 | 28 | 0,2,4,6,7,18,19,37,28 | 9 | 12 |
10 | 0,4,7,8,9,10 | 6 | 38 | 29 | 0,2,5,8,11,15,27,28,29 | 9 | 6 |
11 | 0,4,8,9,10,11 | 6 | 30 | 30 | 0,6,13,18,25,26,27,28,29,30 | 10 | 2 036 |
12 | 0,4,9,10,11,12 | 6 | 14 | 31 | 0,6,13,19,26,27,28,29,30,31 | 10 | 890 |
13 | 0,3,7,11,12,13 | 6 | 6 | 32 | 0,6,13,20,27,28,29,30,31,32 | 10 | 304 |
14 | 0,5,10,11,12,13,14 | 7 | 130 | 33 | 0,5,11,17,23,29,30,31,32,33 | 10 | 120 |
15 | 0,5,11,12,13,14,15 | 7 | 80 | 34 | 0,3,6,10,14,19,31,32,33,34 | 10 | 20 |
16 | 0,4,8,13,14,15,16 | 7 | 32 | 35 | 0,2,8,10,17,19,30,31,34,35 | 10 | 10 |
17 | 0,4,9,14,15,16,17 | 7 | 12 | 36 | 0,1,5,9,16,23,30,33,35,36 | 10 | 2 |
18 | 0,6,13,14,15,16,17,18 | 8 | 500 | 37 | 0,7,15,23,31,32,33,34,35,36,37 | 11 | 2 678 |
19 | 0,5,10,15,16,17,18,19 | 8 | 326 | 38 | 0,6,13,19,26,33,34,35,36,37,38 | 11 | 974 |
20 | 0,5,10,16,17,18,19,20 | 8 | 150 | 39 | 0,6,13,20,27,34,35,36,37,38,38 | 11 | 362 |
21 | 0,5,11,17,18,19,20,21 | 8 | 66 | 40 | 0,5,11,16,23,30,36,37,38,39,40 | 11 | 100 |
5 算法分析
对于优美标号算法,要得到长度为
6 模型推广
挖掘由组合差集递推算法计算出的长度为
定义图
图
图3
由
映射
由
此外,优美图
由定理1,知
即图
由定理
表3 有6~82条边的极小优美图的顶点数f (x)的上下界
Table 3
x | f (x)的上下界 | x | f (x)的上下界 | x | f (x)的上下界 | x | f (x)的上下界 |
---|---|---|---|---|---|---|---|
6 | 4≤f(6)≤4 | 26 | 8≤f(26)≤9 | 46 | 11≤f(46)≤12 | 66 | 12≤f(66)≤15 |
7 | 5≤f(7)≤5 | 27 | 8≤f(27)≤9 | 47 | 11≤f(47)≤13 | 67 | 13≤f(67)≤15 |
8 | 5≤f(8)≤5 | 28 | 8≤f(28)≤10 | 48 | 11≤f(48)≤13 | 68 | 13≤f(68)≤15 |
9 | 5≤f(9)≤5 | 29 | 9≤f(29)≤10 | 49 | 11≤f(49)≤13 | 69 | 13≤f(69)≤15 |
10 | 6≤f(10)≤6 | 30 | 9≤f(30)≤10 | 50 | 11≤f(50)≤13 | 70 | 13≤f(70)≤16 |
11 | 6≤f(11)≤6 | 31 | 9≤f(31)≤10 | 51 | 11≤f(51)≤13 | 71 | 13≤f(71)≤16 |
12 | 6≤f(12)≤6 | 32 | 9≤f(32)≤10 | 52 | 11≤f(52)≤13 | 72 | 13≤f(72)≤16 |
13 | 6≤f(13)≤6 | 33 | 9≤f(33)≤10 | 53 | 11≤f(53)≤13 | 73 | 13≤f(73)≤16 |
14 | 6≤f(14)≤7 | 34 | 9≤f(34)≤10 | 54 | 11≤f(54)≤14 | 74 | 13≤f(74)≤16 |
15 | 6≤f(15)≤7 | 35 | 9≤f(35)≤10 | 55 | 11≤f(55)≤14 | 75 | 13≤f(75)≤16 |
16 | 6≤f(16)≤7 | 36 | 9≤f(36)≤10 | 56 | 12≤f(56)≤14 | 76 | 13≤f(76)≤16 |
17 | 7≤f(17)≤7 | 37 | 10≤f(37)≤11 | 57 | 12≤f(57)≤14 | 77 | 13≤f(77)≤16 |
18 | 7≤f(18)≤8 | 38 | 10≤f(38)≤11 | 58 | 12≤f(58)≤14 | 78 | 13≤f(78)≤16 |
19 | 7≤f(19)≤8 | 39 | 10≤f(39)≤11 | 59 | 12≤f(59)≤14 | 79 | 14≤f(79)≤17 |
20 | 7≤f(20)≤8 | 40 | 10≤f(40)≤12 | 60 | 12≤f(60)≤14 | 80 | 14≤f(80)≤17 |
21 | 8≤f(21)≤8 | 41 | 10≤f(41)≤12 | 61 | 12≤f(61)≤14 | 81 | 14≤f(81)≤17 |
22 | 8≤f(22)≤8 | 42 | 10≤f(42)≤12 | 62 | 12≤f(62)≤15 | 82 | 14≤f(82)≤17 |
23 | 8≤f(23)≤9 | 43 | 10≤f(43)≤12 | 63 | 12≤f(63)≤15 | ||
24 | 8≤f(24)≤9 | 44 | 10≤f(44)≤12 | 64 | 12≤f(64)≤15 | ||
25 | 8≤f(25)≤9 | 45 | 10≤f(45)≤12 | 65 | 12≤f(65)≤15 |
表4 长度为41~82的最省刻度尺的一组最省刻度值
Table 4
直尺长度 | 其中一组包括两端点的最省刻度数值 | 最省刻度数 |
---|---|---|
41 | 0,1,4,10,16,22,28,34,36,39,41 | 11 |
42 | 0,1,2,3,19,24,28,32,36,39,42 | 11 |
43 | 0,1,3,6,13,20,27,34,38,42,43 | 11 |
44 | 0,1,2,3,4,10,16,22,28,34,39,44 | 12 |
45 | 0,1,2,3,4,5,12,20,26,33,39,45 | 12 |
46 | 0,6,13,20,27,34,41,42,43,44,45,46 | 12 |
47 | 0,1,2,3,4,10,17,24,31,36,42,47 | 12 |
48 | 0,1,2,3,23,24,29,33,37,41,45,48 | 12 |
49 | 0,1,2,3,24,29,30,34,38,42,46,49 | 12 |
50 | 0,1,3,6,13,20,27,34,41,45,49,50 | 12 |
51 | 0,1,2,3,4,5,6,7,16,26,34,43,51 | 13 |
52 | 0,1,2,3,4,10,17,24,31,36,42,47,52 | 13 |
53 | 0,7,15,23,31,39,47,48,49,50,51,52,53 | 13 |
54 | 0,1,2,3,4,5,6,14,23,32,39,47,54 | 13 |
55 | 0,1,2,3,4,5,12,20,28,36,42,49,55 | 13 |
56 | 0,1,2,3,27,28,33,37,41,45,49,53,56 | 13 |
57 | 0,1,3,6,13,20,27,34,41,48,52,56,57 | 13 |
58 | 0,1,2,3,27,32,36,40,44,48,52,55,58 | 13 |
59 | 0,1,2,3,4,5,12,20,28,36,42,49,55,59 | 14 |
60 | 0,1,2,3,4,10,17,24,30,37,44,49,55,60 | 14 |
61 | 0,1,2,3,4,5,6,14,23,32,39,47,54,61 | 14 |
62 | 0,1,2,3,4,5,6,14,23,31,40,47,55,62 | 14 |
63 | 0,1,2,3,4,5,6,14,23,32,41,48,56,63 | 14 |
64 | 0,1,3,6,13,20,27,34,41,48,55,59,63,64 | 14 |
65 | 0,1,6,14,22,30,38,46,54,56,58,61,63,65 | 14 |
66 | 0,1,2,3,31,36,40,44,48,52,56,60,63,66 | 14 |
67 | 0,1,2,3,4,5,12,19,26,33,40,47,54,61,67 | 15 |
68 | 0,1,2,3,4,10,17,24,31,38,45,52,57,63,68 | 15 |
69 | 0,1,2,5,12,19,26,33,40,47,54,61,63,67,69 | 15 |
70 | 0,1,2,3,4,5,6,14,23,32,41,48,56,63,70 | 15 |
71 | 0,1,3,6,13,20,27,34,41,48,55,62,66,70,71 | 15 |
72 | 0,1,2,6,14,22,30,38,46,54,62,65,69,71,72 | 15 |
73 | 0,1,6,14,22,30,38,46,54,62,64,66,69,71,73 | 15 |
74 | 0,1,2,3,35,40,44,48,52,56,60,64,68,71,74 | 15 |
75 | 0,1,2,3,4,10,17,24,31,38,45,52,59,64,70,75 | 16 |
76 | 0,1,2,5,12,19,26,33,40,47,54,61,68,70,74,76 | 16 |
77 | 0,1,2,3,4,5,6,14,22,30,38,46,54,62,70,77 | 16 |
78 | 0,1,3,6,13,20,27,34,41,48,55,62,69,73,77,78 | 16 |
79 | 0,1,2,3,4,5,12,20,28,36,44,52,60,66,73,79 | 16 |
80 | 0,1,2,3,4,5,6,14,23,32,40,49,58,65,73,80 | 16 |
81 | 0,1,2,3,4,5,6,7,16,26,36,46,56,64,73,81 | 16 |
82 | 0,1,2,3,39,44,48,52,56,60,64,68,72,76,79,82 | 16 |
7 结 语
具有
求长度为
http://dx.doi.org/10.3785/j.issn.1008-9497.2024.02.006
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