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A reversible prime in any number system is a prime whose "reverse" in that number system is also a prime. For example in the decimal system 73 is a re 阅读全文
摘要：
To evaluate the performance of our first year CS majored students, we consider their grades of three courses only: C Programming Language, Mathematics 阅读全文
摘要：
It is vitally important to have all the cities connected by highways in a war. If a city is occupied by the enemy, all the highways from/toward that c 阅读全文