摘要： The Embarrassed CryptographerTime Limit: 2000MSMemory Limit: 65536KTotal Submissions: 9291Accepted: 2403DescriptionThe young and very promising cryptographer Odd Even has implemented the security module of a large system with thousands of users, which is now in use in his company. The cryptographic 阅读全文

摘要： Brackets SequenceTime Limit: 1000MSMemory Limit: 65536KTotal Submissions: 18313Accepted: 5020Special JudgeDescriptionLet us define a regular brackets sequence in the following way: 1. Empty sequence is a regular sequence. 2. If S is a regular sequence, then (S) and [S] are both regular sequences. 3. 阅读全文