随笔分类 - 优化技巧
摘要：2957: 楼房重建 Description 小A的楼房外有一大片施工工地，工地上有N栋待建的楼房。每天，这片工地上的房子拆了又建、建了又拆。他经常无聊地看着窗外发呆，数自己能够看到多少栋房子。 为了简化问题，我们考虑这些事件发生在一个二维平面上。小A在平面上(0,0)点的位置，第i栋楼房可以用一条
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摘要：4883: [Lydsy1705月赛]棋盘上的守卫 Description 在一个n*m的棋盘上要放置若干个守卫。对于n行来说，每行必须恰好放置一个横向守卫；同理对于m列来说，每列 必须恰好放置一个纵向守卫。每个位置放置守卫的代价是不一样的，且每个位置最多只能放置一个守卫，一个守卫 不能同时兼顾行列
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摘要：题意：给定A，B长度相同的字符串，Q次操作，修改操作位单个字符修改，查询操作为询问从某点开始有多少连续相同的字符。 思路：我们把不相同的设为1，相同的设为0，那么询问就是找下一个为1的为位置，可以用线段树解决，可以用set的lower_bound解决，这里用bitset的Find_next函数，效率
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摘要：Collecting one's own plants for use as herbal medicines is perhaps one of the most self-empowering things a person can do, as it implies that they hav
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摘要：题意：给出，三个函数，h，b，a，然后T次询问，每次给出n，求sqrt(an); 思路：不会推，但是感觉a应该是线性的，这个时候我们就可以用BM线性递推，自己求出前几项，然后放到模板里，就可以求了。 数据范围在1e15，1000组都可以秒过。 （ 那么主要的问题就是得确保是线性的，而且得求出前几项。
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摘要：Yellowstar likes integers so much that he listed all positive integers in ascending order,but he hates those numbers which can be written as a^b (a, b
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摘要：There are n numbers 3^0, 3^1, . . . , 3^n-1. Each time you can choose a subset of them (may be empty), and then add them up. Count how many numbers ca
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摘要：There is a tree having N vertices. In the tree there are K monkeys (K <= N). A vertex can be occupied by at most one monkey. They want to remove some
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摘要：Give an array A, the index starts from 1. Now we want to know B i =max i∤j A j Bi=maxi∤jAj , i≥2 i≥2 . InputThe first line of the input gives the numb
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摘要：Little Ruins is playing a number game, first he chooses two positive integers yy and KK and calculates f(y,K)f(y,K), here f(y,K)=∑z in every digits of
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摘要：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
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摘要：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
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摘要：One day Natalia was walking in the woods when she met a little mushroom gnome. The gnome told her the following story: Everybody knows that the mushro
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摘要：Little Artem has invented a time machine! He could go anywhere in time, but all his thoughts of course are with computer science. He wants to apply th
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摘要：Factorial numbers are getting big very soon, you'll have to compute the number of divisors of such highly composite numbers. Input The first line cont
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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
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摘要：We already know of the large corporation where Polycarpus works as a system administrator. The computer network there consists of n computers and m ca
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摘要：Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or filled with wa
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摘要：描述 给定N个正整数A1, A2, ... AN。 小Hi希望你能从中选出M个整数，使得它们的乘积末尾有最多的0。 输入 第一行包含两个个整数N和M。 第二行包含N个整数A1, A2, ... AN。 对于30%的数据，1 ≤ M ≤ N ≤ 12 对于100%的数据，1 ≤ M ≤ N ≤ 100
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摘要：Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of i
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