題目網址: http://www.puzzleup.com/2018/
http://www.puzzleup.com/2018/puzzle/?5
答題時限: 8月30日7PM-比賽結束(約12月12日)
加分時限: 8月30日7PM-9月5日6:59PM
答對可得基本分100分。答案可上傳5次,每改1次答案從基本分扣20分。
比賽期間內可隨時上傳答案,加分時限內答對第n天加(6-n)分
另依題目的難易有額外加分(如有80%的人這題答錯,答對者加80分)
◆NUMBER SELECTION
Given any X integers (not necessarily distinct), if it is always possible to
select Y of them whose sum is divisible by 7, what is the minimum value of X
and the corresponding value of Y?
Note: X and Y are positive integers.
If the same question were asked for divisibility by 2, the minimum value of X
would be 3 and the corresponding value of Y would be 2.
Enter the minimum X, then the corresponding Y without using a space in between.
給予X個任意整數(可以重覆),一定能從中挑選出Y個數,使其總和能整除於7,則X的最
小值與其相應的Y值呢?
註:X與Y都是正整數。
若題目要求整除於2,則X的最小值會是3,相對應的Y會是2。
輸入最小的X,接著相對應的Y,中間無需空格。