题目网址: https://www.puzzleup.com/2020/ https://www.puzzleup.com/2020/puzzle/?1 答题时限: 11月５日７ＰＭ－比赛结束（约12月30日） 加分时限: 11月５日７ＰＭ－11月10日６：５９ＰＭ 答对可得基本分１００分。答案可上传５次，每改１次答案从基本分扣２０分。　 比赛期间内可随时上传答案，加分时限内答对第ｎ天加（６－ｎ）分　 　　 　　 另依题目的难易有额外加分（如有８０％的人这题答错，答对者加８０分）　　 ◆TETRAHEDRON TRAVEL https://www.puzzleup.com/2020/img/puzzle/2020/01.jpg You will make a travel through the edges of two tetrahedrons (ABCD, and CDEF) joined as shown in the figure. - You will start on A, and finish on F. - You can visit the vertices more than once except the finishing vertex F. - You can't pass through the edges more than once. In how many different ways can this travel be done? Note: Two travels having same edges in different order will be considered as different. 你将从上图这两个正四面体 (ABCD 及 CDEF) 在一个边相接的图形的边上进行移动。 - 路线从 A 开始，到 F 结束。 - 除了 F 之外的任一顶点皆可以经过多於一次。 - 任一条边不能经过多於一次。 试问如此的移动有多少种不同的走法？ 注意: 两个走法若仅是经过的边顺序不同依然视为不同走法。 ==== 第一题是个旧题形回顾, 之前出在 2015 Q9 和 2016 Q10 那因为同样几乎一字不改我就把旧翻译拿来用了 XD -- 'You've sort of made up for it tonight,' said Harry. 'Getting the sword. Finishing the Horcrux. Saving my life.' 'That makes me sound a lot cooler then I was,' Ron mumbled. 'Stuff like that always sounds cooler then it really was,' said Harry. 'I've been trying to tell you that for years.' -- Harry Potter and the Deathly Hollows, P.308 --

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