04 2018 档案
摘要：On September 22, 2004, Oceanic Flight 815 crashed on a mysterious island somewhere in the pacific. There actually were survivors in the crash , N surv
阅读全文
摘要：Rastas's has been given a number n. Being weak at mathematics, she has to consider all the numbers from 1 to 2n - 1 so as to become perfect in calcula
阅读全文
摘要：Shadowman loves to collect box but his roommates woogieman and itman don't like box and so shadowman wants to hide boxes as many as possible. A box ca
阅读全文
摘要：Problem statement: A string is said to be “PATHETIC” if all the characters in it are repeated the same number of times. You are given a string of leng
阅读全文
摘要：You are given N(1<=N<=100000) integers. Each integer is square free(meaning it has no divisor which is a square number except 1) and all the prime fac
阅读全文
摘要：Given an array of N integers A1, A2, A3…AN. If you randomly choose two indexes i ,j such that 1 ≤ i < j ≤ N, what is the expected value of Ai | Aj? In
阅读全文
摘要：。。。
阅读全文
摘要：ultmaster 男神和小迷妹们玩起了捉迷藏的游戏。 小迷妹们都希望自己被 ultmaster 男神发现，因此她们都把自己位置告诉了 ultmaster 男神，因此 ultmaster 男神知道了自己去找每个小迷妹所要花的时间。 已知发现第 i 小迷妹得到的分数为 ai⋅tr（tr 为游戏剩余时间
阅读全文
摘要：Waca loves maths,.. a lot. He always think that 1 is an unique number. After playing in hours, Waca suddenly realize that every integer can be represe
阅读全文
摘要：As you might already know, Ada the Ladybug is a farmer. She grows a big fruit tree (with root in 0). There is a fruit on every node of the tree. Ada i
阅读全文
摘要：Ada the Ladybug lives near an orange tree. Instead of reading books, she investigates the oranges. The oranges on orange tree can be in up to 5*50 Sha
阅读全文
摘要：Rainbow 6 is a very popular game in colleges. There are 2 teams, each having some members and the 2 teams play some matches against each other. The te
阅读全文
摘要：ps：感觉比昨天晚上的华师题目质量高一点，至少emmm，题面没有那么多bug。 下面忽略了水题，只给出我觉得有价值的几个题目的题解和代码： 【C:神山神石】： 题意： 每一天，Wells可以喂神山一个神石，使得神山的高度变为原高度乘上神石的能力值，或者使得所有的神石能力值+1。第 0 天时，所有神石
阅读全文
摘要：Problem description. The Fibonacci numbers defined as f(n) = f(n-1) + f(n-2) where f0 = 0 and f1 = 1. We define a function as follows D(n,x) = x + x^2
阅读全文
摘要：You are given an array of size N. How many distinct arrays can you generate by swapping two numbers for exactly once? The two selected numbers can be
阅读全文
摘要：Katniss Everdeen after participating in Hunger Games now wants to participate in NT Games (Number Theory Games). As she begins President Snow provides
阅读全文
摘要：Dima adds letters s1, …, sn one by one to the end of a word. After each letter, he asks Misha to tell him how many new palindrome substrings appeared
阅读全文
摘要：The northern part of the Pyramid contains a very large and complicated labyrinth. The labyrinth is divided into square blocks, each of them either fil
阅读全文
摘要：A positive integer is called a palindrome if its representation in the decimal system is the same when read from left to right and from right to left.
阅读全文
摘要：Misha and Dima are promising young scientists. They make incredible discoveries every day together with their colleagues in the Spilkovo innovative ce
阅读全文
摘要：Do you think that magic is simple? That some hand-waving and muttering incomprehensible blubber is enough to conjure wonderful gardens or a fireball t
阅读全文
摘要：Misha trains several ACM teams at the university. He is an experienced coach, and he does not underestimate the meaning of friendly and collaborative
阅读全文
摘要：The hacker Michael develops breakthrough password manager, which is called KEK (Keeper of Encrypted Keys). A distinctive feature of KEK is excellent s
阅读全文
摘要：There is a strip 1 × n with two sides. Each square of the strip (their total amount is 2n, n squares on each side) is painted in one of two colors (le
阅读全文
摘要：FJ is about to take his N (1 ≤ N ≤ 2,000) cows to the annual"Farmer of the Year" competition. In this contest every farmer arranges his cows in a line
阅读全文
摘要：占位
阅读全文
摘要：很久很久以前，在你刚刚学习字符串匹配的时候，有两个仅包含小写字母的字符串A和B，其中A串长度为m，B串长度为n。可当你现在再次碰到这两个串时，这两个串已经老化了，每个串都有不同程度的残缺。 你想对这两个串重新进行匹配，其中A为模板串，那么现在问题来了，请回答，对于B的每一个位置i，从这个位置开始连续
阅读全文
摘要：把每一位看成ai*10^i，然后就是两个多项式相乘。利用FFT，把复杂度降到O（nlogn）。
阅读全文
摘要：FFT在用于解决多项式乘法A*B（A和B为多项式，形如a0+a1*x^1+a2*x^2....）的时候，通俗地解释就是： 原理：先根据各自的系数各自转化为对应的向量（O(nlogn)），然后向量相乘（O(n)），最后再还原得到相乘后的系数（O(nlogn)）。 手段：利用了虚数，使得可以分治来快速求
阅读全文
摘要：You're given a sequence s of N distinct integers.Consider all the possible sums of three integers from the sequence at three different indicies.For ea
阅读全文
摘要：思路：树状结构，改变权值其实是删一条边和加一条边，所以转化为LCT题。 优化：开始建树（原树，一共N条边，根为N+1）的时候，由于原树的虚拟的，我们不一定要把N条边都Link，而是可以直接记录fa即可。 当然还可以用分块做。但是没有LCT直观。
阅读全文
摘要：题意：给定N点M边的无向图，每边有权值，Q次询问，每次询问给出u、v，回答u到v的所有路径中最大边的最小值。 思路：常识可知，需要最小生成树，然后就是最小生成树两点间的最大值。 可以用树剖+线段树解决 。或者动态树LCT姿势搞定。 （写LCT写惯了就不想写树剖了有没有
阅读全文
摘要：题意：给定一个无向图，每条边有两个权值ai和bi，从1走到N，设路径上a权的最大值为A，b权的最大值为B，求A+B的最小值。n<=5*1e4. m<=5*1e4。 思路：要生成最小生成树（至少满足1和N连通），我们选择的边如果按A递增，那么易得B递减。现在按a从小到大排序，得到对于每个a，找到对应的
阅读全文
摘要：题意：给定N个节点的初始值，现在有M个操作，每次输入opt、x、y，opt情况如下。 ０：输出x到y的路径异或和保证ｘ到ｙ是联通的。 １：连接x和y，已经连通则忽略。 ２：删除边x和y，如果不连通则忽略。（题目的连通应该还保证了是直接相邻，不然需要记录直接相邻的关系）。 ３：把节点x的值改为y。 思
阅读全文
摘要：题意：给定N个岛屿，每个岛屿有初始数量的企鹅。现在有如下三种操作： 1. "bridge A B"—— 在A与B之间建立一座大桥（A与B是不同的岛屿）。如果A、B连通，输出"yes"，且建造这座大桥。否则，输出"no"。 2. "penguins A X"——岛屿A此时的帝企鹅数量变为X。 3. "
阅读全文
摘要：题意：一个森林，有三种操作。 L，u，v： 在u和v之间加一条边。 C，u，v：删去u和v之间的边。 Q，u，v：查询u和v是否在同一棵树里。 思路：简单的LCT。 具体的： 关于查找两个节点X、Y是否在同一棵树上：因为splay的根节点是不固定的，也没有代表性，所以需要找“原树”的根节点。 具体的
阅读全文
摘要：【参考】：我觉得写得最清楚的一个：https://oi.men.ci/link-cut-tree-notes/ https://www.cnblogs.com/flashhu/p/8324551.html 论文什么的太专业了我一半没耐心去看：https://wenku.baidu.com/view/
阅读全文
