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Canterbury Puzzle 19 · Nine Counters 19

题面摘自 Henry E. Dudeney 公版文本;英文为古腾堡原文整理,中文为本站自译,提示、解答骨架和闲谈保留本站原创结构。

The Canterbury Puzzles 1907 19 combinatorial

The Prioress, who went by the name of Eglantine, is best remembered on account of Chaucer's remark, "And French she spake full fair and properly, After the school of Stratford-atté-Bow, For French of Paris was to her unknow." But our puzzle has to do less with her character and education than with her dress. "And thereon hung a brooch of gold full sheen, On which was written first a crownéd A." It is with the brooch that we are concerned, for when asked to give a puzzle she showed this jewel to the company and said: "A learned man from Normandy did once give me this brooch as a charm, saying strange and mystic things anent it, how that it hath an affinity for the square, and such other wise words that were too subtle for me. But the good Abbot of Chertsey did once tell me that the cross may be so cunningly cut into four pieces that they will join and make a perfect square; though on my faith I know not the manner of doing it." It is recorded that "the pilgrims did find no answer to the riddle, and the Clerk of Oxenford thought that the Prioress had been deceived in the matter thereof; whereupon the lady was sore vexed, though the gentle knight did flout and gibe at the poor clerk because of his lack of understanding over other of the riddles, which did fill him with shame and make merry the company."

这位名叫艾格兰汀的女修道院院长因乔叟的一句话而被人们铭记:“在斯特拉特福·阿泰·鲍的学校之后,她说的法语完全公平而得体,因为她不知道巴黎的法语。”但我们的困惑与其说与她的性格和教育有关,不如与她的着装有关。 “其上挂着一枚金光闪闪的胸针,上面首先写着一个戴着王冠的A。”我们关心的是这枚胸针,因为当被要求解谜时,她向大家展示了这颗宝石,并说道:“一位来自诺曼底的学者曾送给我这枚胸针作为护身符,他对它说了一些奇怪而神秘的事情,它如何与正方形有密切的关系,以及其他对我来说太微妙的明智之词。但是,善良的彻特西修道院院长曾经告诉我,十字架可以被巧妙地切成四块,它们将连接在一起,形成一个完美的十字架。”方形;尽管我不知道该怎么做。”据记载,“朝圣者们没有找到谜语的答案,奥克森福德的书记员认为女修道院院长在这件事上被欺骗了;于是这位女士非常恼火,尽管这位温柔的骑士因为对其他谜语缺乏理解而对可怜的书记员进行了蔑视和嘲笑,这确实让他感到羞愧,并使同伴们感到高兴。”

提示 1

先把每一步允许做什么写成状态表。

提示 2

找一个不会随操作改变的量,或把对象分成互斥类别。

提示 3

检查构造是否覆盖全部对象,而不是只给出一个漂亮例子。

完整解答

固定主人面向门口,就消除了旋转重复。先数其余人任意排列,再减去两位指定朝圣者相邻的情形。相邻时把这两人看成一个双人块,块内部有 2 种顺序;最后用总数减去坏排列。

Dudeney 的趣题常把难点藏在“看起来可以试”的地方。别急着猜答案;先把图、表或状态画出来,再问哪些限制一直没有变。这也是它和 Carroll 逻辑题互补的地方:一个拆句子,一个拆结构。