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题意：给定N个节点，K次操作，操作有两种，1是合并两个集合，2是求某个集合的第K大（从小到大排序）。 思路：合并只要启发式即可。此题可以用线段树，保存1到N的排序的出现次数和。 复杂度O（NlogN）。想象一下，当其中一棵树节点少的时候，复杂度是O(logN)的，次数不超过N次；当两棵树的节点都蛮多 阅读全文
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Yash is finally tired of computing the length of the longest Fibonacci-ish sequence. He now plays around with more complex things such as Fibonacci-is 阅读全文
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题意：给出N，K，M，P。求有多少长度为K的序列A，满足：（1）首项为正整数；（2）递增数列；（3）相邻两项的差小于等于m；（4）最后一个数小于等于N。 思路：根据差分来算数量。 阅读全文
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There is a sequence aa of length nn. We use aiai to denote the ii-th element in this sequence. You should do the following three types of operations t 阅读全文
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At the children's day, the child came to Picks's house, and messed his house up. Picks was angry at him. A lot of important things were lost, in parti 阅读全文
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有M个球，一开始每个球均有一个初始标号，标号范围为1～N且为整数，标号为i的球有ai个，并保证Σai = M。 每次操作等概率取出一个球（即取出每个球的概率均为1/M），若这个球标号为k（k < N），则将它重新标号为k + 1；若这个球标号为N，则将其重标号为1。（取出球后并不将其丢弃） 现在你需 阅读全文
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On Saint Valentine's Day, Alex imagined to present a special pendant to his girl friend made by K kind of pearls. The pendant is actually a string of 阅读全文
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A cellular automaton is a collection of cells on a grid of specified shape that evolves through a number of discrete time steps according to a set of 阅读全文
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题意：输入N，输出fib(2^N)%1125899839733759。（P=1125899839733759是素数） 思路：欧拉降幂，因为可以表示为矩阵乘法，2^N在幂的位置，矩阵乘法也可以降幂，所以有ans=a*base^num; num=2^N%(P-1)。 阅读全文
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JRY wants to drag racing along a long road. There are nn sections on the road, the ii-th section has a non-negative integer length sisi. JRY will choo 阅读全文