逆水行舟 不进则退

Problem DescriptionIt is well known that small groups are not conducive of the development of a team. Therefore, there shouldn’t be any small groups in a good team.In a team with n members,if there

给定一个完全由小写英文字母组成的字符串等差递增序列，该序列中的每个字符串的长度固定为 L，从 L 个 a 开始，以 1 为步长递增。例如当 L 为 3 时，序列为 { aaa, aab, aac, ..., aaz, aba, abb, ..., abz, ..., zzz }。这个序列的倒数第27个字符串就是 zyz。对于任意给定的 L，本题要求你给出对应序列倒数第 N 个字符串。输入格

Problem DescriptionNowadays, little haha got a problem from his teacher.His teacher wants to design a big logo for the campus with some circles tangent with each other. And now, here comes the proble

roblem DescriptionWe define Zhu(G) as the value of G.( G is labeled undirected graphs with n nodes( self-loop and multiple edge are not allowed ) ).The method of calculating Zhu(G) is easy , if G h

Problem DescriptionThe Karting championship will be held on a straight road. There are N keypoints on the road. The path between keypoint i and i+1 has a degree of difficulty Di(Di may be negative if

Problem DescriptionAs we all know,a palindrome number is the number which reads the same backward as forward,such as 666 or 747.Some numbers are not the palindrome numbers in decimal form,but in othe

Problem DescriptionToday is the birthday of SF,so VS gives two strings S1,S2 to SF as a present,which have a big secret.SF is interested in this secret and ask VS how to get it.There are the things t

Problem Description"You shall not pass!"After shouted out that,the Force Staff appered in CaoHaha's hand.As we all know,the Force Staff is a staff with infinity power.If you can use it skillful,it

Problem DescriptionAs we know, minimumvertexcover is a classical NP-complete problem. There will not be polynomial time algorithm for it unless P=NP.You can see the definition of vertex cover in ht

Problem DescriptionQscqesze is going to hold a blind date party.He takes n boys and m girls into consideration of invitation.Each of them gets a number as a1..an and b1..bm.The party is in pairs.Eve

L1-6 福到了（15 分）“福”字倒着贴，寓意“福到”。不论到底算不算民俗，本题且请你编写程序，把各种汉字倒过来输出。这里要处理的每个汉字是由一个 N × N 的网格组成的，网格中的元素或者为字符 @ 或者为空格。而倒过来的汉字所用的字符由裁判指定。输入格式：输入在第一行中给出倒过来的汉字所用的字符、以及网格的规模 N （不超过100的正整数），其间以 1 个空格分隔；随后 N 行，每行给出 N...