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摘要： Power of CryptographyBackgroundCurrent work in cryptography involves (among other things) large prime numbers and computing powers of numbers modulo functions of these primes. Work in this area has resulted in the practical use of results from number theory and other branches of mathematics once con 阅读全文

摘要： The ? 1 ? 2 ? ... ? n = k problemThe problemGiven the following formula, one can set operators '+' or '-' instead of each '?', in order to obtain a given k? 1 ? 2 ? ... ? n = kFor example: to obtaink = 12, the expression to be used will be:- 1 + 2 + 3 + 4 + 5 + 6 - 7 = 12with 阅读全文

摘要： Secret ResearchAt a certain laboratory results of secret research are thoroughly encrypted. A result of a single experiment is stored as an information of its completion:`positive result', `negative result', `experiment failed' or `experiment not completed'The encrypted result consti 阅读全文

摘要： The SnailA snail is at the bottom of a 6-foot well and wants to climb to the top. The snail can climb 3 feet while the sun is up, but slides down 1 foot at night while sleeping. The snail has a fatigue factor of 10%, which means that on each successive day the snail climbs 10%3 = 0.3 feet less than 阅读全文