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Give a tree with n vertices,each edge has a length(positive integer less than 1001).Define dist(u,v)=The min distance between node u and v.Give an int 阅读全文
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Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration (that must be going th 阅读全文
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A positive integer aa is given. Baron Munchausen claims that he knows such a positive integer nn that if one multiplies nn by aa, the sum of its digit 阅读全文
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Bizon the Champion isn't just charming, he also is very smart. While some of us were learning the multiplication table, Bizon the Champion had fun in 阅读全文
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A string is binary, if it consists only of characters "0" and "1". String v is a substring of string w if it has a non-zero length and can be read sta 阅读全文
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Berland starts to seize the initiative on the war with Flatland. To drive the enemy from their native land, the berlanders need to know exactly how ma 阅读全文
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Little Petya likes points a lot. Recently his mom has presented him n points lying on the line OX. Now Petya is wondering in how many ways he can choo 阅读全文
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Some people believe that there are three cycles in a person's life that start the day he or she is born. These three cycles are the physical, emotiona 阅读全文
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People are different. Some secretly read magazines full of interesting girls' pictures, others create an A-bomb in their cellar, others like using Win 阅读全文
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This problem is based on an exercise of David Hilbert, who pedagogically suggested that one study the theory of 4n+1 numbers. Here, we do only a bit o 阅读全文