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摘要：Description Let us consider the sequence a1, a2,..., an of non-negative integer numbers. Denote as ci,j the number of occurrences of the number i amon 阅读全文

摘要：Description For a set of sequences of integers｛a1，a2，a3，...an｝, we define a sequence｛ai1,ai2,ai3...aik｝in which 1<=i1<i2<i3<...<ik<=n, as the sub-sequ 阅读全文

摘要：Problem Description After inventing Turing Tree, 3xian always felt boring when solving problems about intervals, because Turing Tree could easily have 阅读全文

摘要：Problem Description Tired of playing computer games, alpc23 is planning to play a game on numbers. Because plus and subtraction is too easy for this g 阅读全文

摘要：Problem Description The inversion number of a given number sequence a1, a2, ..., an is the number of pairs (ai, aj) that satisfy i < j and ai > aj.For 阅读全文

摘要：Problem Description C国的死对头A国这段时间正在进行军事演习，所以C国间谍头子Derek和他手下Tidy又开始忙乎了。A国在海岸线沿直线布置了N个工兵营地,Derek和Tidy的任务就是要监视这些工兵营地的活动情况。由于采取了某种先进的监测手段，所以每个工兵营地的人数C国都掌握的 阅读全文

摘要：学长的浅谈线段树~~~ 阅读全文