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1352. Mersenne PrimesTime limit: 1.0 secondMemory limit: 64 MBDefinition.If the number 2N−1 is prime then it is called aMersenne prime number.For example, 22−1 — the first Mersenne prime, 23−1 — the second Mersenne prime, 211213−1 — the 23rd, 2216091−1 — the 31st.It’s a hard problem to find those nu 阅读全文
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1086. CryptographyTime limit: 2.0 secondMemory limit: 64 MBWhile preparing this problem set the jury has run into the following problem: it was necessary to send by e-mail the texts of the problems. As it is well known, e-mail is not reliable, messages are sent not enciphered, there is a danger that 阅读全文