摘要：
DescriptionLet us define a regular brackets sequence in the following way:Empty sequence is a regular sequence.If S is a regular sequence, then (S) an... 阅读全文
摘要：
DescriptionThe railway line “Yekaterinburg-Sverdlovsk” with several stations has been built. This railway line can be represented as a line segment, r... 阅读全文
摘要：
DescriptionOnce upon a time an Eagle made a nest on the roof of a very large building. Time went by and some eggs appeared in the nest. There was a su... 阅读全文
摘要：
DescriptionMr. F. wants to get a document be signed by a minister. A minister signs a document only if it is approved by his ministry. The ministry is... 阅读全文
摘要：
DescriptionYou are given a number 1 ≤N≤ 50. Every ticket has its 2N-digit number. We call a ticket lucky, if the sum of its firstNdigits is equal to t... 阅读全文
摘要：
DescriptionThe owner of a casino for New Russians has a very refined sense of beauty. For example, after a game there remain two piles with the same n... 阅读全文
摘要：
DescriptionLet's remember one old joke:Once a gentleman said to another gentleman:— What if we play cards?— You know, I haven't played cards for ten y... 阅读全文
摘要：
DescriptionKolya has returned from a summer camp and now he's a realcommunication fiend. He spends all his free time on the Web chatting with his frie... 阅读全文