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k-Tree CodeForces - 431C Quite recently a creative student Lesha had a lecture on trees. After the lecture Lesha was inspired and came up with the tre 阅读全文
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Cd and pwd commands CodeForces - 158C Vasya is writing an operating system shell, and it should have commands for working with directories. To begin w 阅读全文
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Replacement CodeForces - 570C 话说很久很久以前，孙悟空被压在了山下，很无聊。于是他找了一个只包含小写字母和字符"." 的字符串。 由于他比较无聊，他就开始了换点点，他找到字符串中第一个出现的".."，然后把其换成"."。 如果字符串中不包含".."，换点点操作对字符串无 阅读全文
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Design Tutorial: Make It Nondeterministic CodeForces - 472C A way to make a new task is to make it nondeterministic or probabilistic. For example, the 阅读全文
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Team CodeForces - 401C Now it's time of Olympiads. Vanya and Egor decided to make his own team to take part in a programming Olympiad. They've been be 阅读全文
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Lucky Numbers CodeForces - 630C 小希称只含7和8的数是幸运数，那么不超过n位的幸运数有多少个？ Input 一个整数 n (1 ≤ n ≤ 55) Output 输出幸运数的数量 Example Input 2 Input 2 Output 6 sol：这和0,1有个 阅读全文
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Developing Skills CodeForces - 581C 你在玩一个游戏.你操作的角色有n个技能,每个技能都有一个等级ai.现在你有k次提升技能的机会(将其中某个技能提升一个等级,可以重复提升某一个等级).但技能的等级不能超过100.你可以不用用完全部的k次机会.已知角色的能力值=∑( 阅读全文
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Vanya and Exams CodeForces - 492C Vanya wants to pass n exams and get the academic scholarship. He will get the scholarship if the average grade mark 阅读全文