摘要： 从放暑假前周sir给我讲了一个用polya计数法和burnside定理做的题目（pku2409）后，突然觉得组合数学挺有意思，然后从那时起到现在几乎都在做这类的题目。做到现在感觉这类题目的一些基本知识点都差不多有所了解了，水题也刷了不少，但还有很多难题自己实在是做不动，所以准备把这类题目先放一放，然后把前段时间做的水题整理一下（供以后的初学者参考，大牛就不要看了哈，都是水题）。剩下的比较难的题目就慢慢来吧，以后做出来再不上，这个小结会不断地更新。也希望大家有好的题目可以推荐一下，分享一下哈。感谢：周sir，J_factory和福州大学神牛aekdycoin，大连理工大学神牛czyuan。不扯了 阅读全文

摘要： Starship TroopersTime Limit: 10000/5000 MS (Java/Others)Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5726Accepted Submission(s): 1529Problem DescriptionYou, the leader of Starship Troopers, are sent to destroy a base of the bugs. The base is built underground. It is actually a huge 阅读全文

摘要： ComputerTime Limit: 1000/1000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1232Accepted Submission(s): 597Problem DescriptionA school bought the first computer some time ago(so this computer's id is 1). During the recent years the school bought N-1 new computers. 阅读全文

摘要： Anniversary partyTime Limit: 2000/1000 MS (Java/Others)Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 2124Accepted Submission(s): 896Problem DescriptionThere is going to be a party to celebrate the 80-th Anniversary of the Ural State University. The University has a hierarchical struc 阅读全文