题目网址: http://www.puzzleup.com/2019/
http://www.puzzleup.com/2019/puzzle/?20
答题时限: 12月5日７ＰＭ－比赛结束
加分时限: 12月5日７ＰＭ－12月11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）
◆WEIGHING SET
You will specify three weights to form a weighing set and you will take
three of each weight. Your aim is to weigh all the integer weights from
1 to N using these nine weights in a two-tier balance scale.
What is the maximum number of N?
Notes:
‧ You can put weights on both sides of the scale.
‧ Each integer weight you weigh should be in balance.
为了构成测量用的组合，你要给定三个重量，然后将每个重量的砝码各取三颗。
目标是用双头天平加上这九颗砝码去量测1到N的所有整数重量出来。
问N的最大值为？
注：
．天平两端皆可放砝码。
．每个可以量测的整数重量都要衡平。