HPrefix Sum study from : https://blog.csdn.net/mitsuha_/article/details/81774727 k较小.分离x和k. 另外的可能:求a[k][x],x不确定,想到的是求sum(a[k][1]+a[k][2]+...+a[k][x]),树状数组 sum(x)-sum(x-1).这题用不上. #include <cstdio> #include <cstdlib> #include <cmath> #incl…

链接:牛客网暑期ACM多校训练营(第四场):A Ternary String 题意:给出一段数列 s,只包含 0.1.2 三种数.每秒在每个 2 后面会插入一个 1 ,每个 1 后面会插入一个 0,之后第一个数字消失.求最后为空串需要多少秒. 题解: (1)如果在消除一个 0 前经过了 n 秒,那么消掉这个 0 需要 n + 1 秒. (2)如果在消除一个 1 前经过了 n 秒,那么消掉这个 1 与其产生的所有数需要 (n + 1) * 2 秒. (3)如果在消除一个 2 前经过了 n 秒,那么…

链接:牛客网暑期ACM多校训练营(第五场):F - take 题意: Kanade有n个盒子,第i个盒子有p [i]概率有一个d [i]大小的钻石. 起初,Kanade有一颗0号钻石.她将从第1到第n打开盒子.当她打开一个盒子时,如果里面有一颗钻石并且比它的钻石大,那么她将用她的钻石代替它. 现在您需要计算预期的替换次数. 您只需要输出答案模块998244353. 注意:如果x%998244353 = y * d%998244353,那么我们表示x / y%998244353 = d%99824…

牛客网暑期ACM多校训练营(第二场) 水博客. A.run 题意就是一个人一秒可以走1步或者跑K步,不能连续跑2秒,他从0开始移动,移动到[L,R]的某一点就可以结束.问一共有多少种移动的方式. 个人感觉是带约束条件的超级楼梯问题.说是dp其实就是递推吧.只要连续的两秒不是跑的就可以.所以在已经跑了i步的时候,直接考虑最后一步是跑的还是走的就可以了. 所以公式就是dp[i]=dp[i-1]+dp[i-1-k];然后前缀和预处理一下,直接从L的for到R的就可以了. 反正乱七八糟就出来了.现在写题…

牛客网暑期ACM多校训练营(第一场) A.Monotonic Matrix 这个题就是给你一个n*m的矩阵,往里面填{0,1,2}这三种数,要求是Ai,j⩽Ai+1,j,Ai,j⩽Ai,j+1 ,问你一共有几种填法. 变形一下就会发现其实是走非交叉格子路径计数,限制条件下的非降路径问题.就是从左上到右下走格子路径.从上到下为0——n,从左到右为0——m. 考虑 01 和 12 的分界线,是 (n, 0) 到 (0, m) 的两条不相交(可重合)路径,因为起点重合了,所以把其中一条路径往左上平移了…

牛客网暑期ACM多校训练营(第三场)H Diff-prime Pairs (贡献) 链接:https://ac.nowcoder.com/acm/contest/141/H来源:牛客网 Eddy has solved lots of problem involving calculating the number of coprime pairs within some range. This problem can be solved with inclusion-exclusion meth…

2018牛客网暑期ACM多校训练营(第二场)I- car 链接:https://ac.nowcoder.com/acm/contest/140/I来源:牛客网 时间限制:C/C++ 1秒,其他语言2秒 空间限制:C/C++ 131072K,其他语言262144K 64bit IO Format: %lld 题目描述 White Cloud has a square of n*n from (1,1) to (n,n). White Rabbit wants to know the maximum…

链接:https://www.nowcoder.com/acm/contest/145/C 来源:牛客网 题目描述 A binary string s of length N = 2n is given. You will perform the following operation n times : - Choose one of the operators AND (&), OR (|) or XOR (^). Suppose the current and s2i. For examp…

链接:https://www.nowcoder.com/acm/contest/139/J来源:牛客网 时间限制:C/C++ 2秒,其他语言4秒 空间限制:C/C++ 524288K,其他语言1048576K 64bit IO Format: %lld 题目描述 Given a sequence of integers a1, a2, ..., an and q pairs of integers (l1, r1), (l2, r2), ..., (lq, rq), find count(l1,…

链接:https://www.nowcoder.com/acm/contest/147/A来源:牛客网 Niuniu has recently learned how to use Gaussian elimination to solve systems of linear equations. Given n and a[i], where n is a power of 2, let's consider an n x n matrix A. The index of A[i][j] an…

链接:https://www.nowcoder.com/acm/contest/147/D来源:牛客网 Niuniu likes traveling. Now he will travel on a special graph. Given k and n, The directed graph contains n vertices, which are numbered from 0 to n - 1. For the vertex i, and for 1 <= j <= k, ther…

https://www.nowcoder.com/acm/contest/144/G 链接:https://www.nowcoder.com/acm/contest/144/G来源:牛客网 In Viridian forest there is a tree T formed by N nodes, each edge on which has a positive weight. There is an undirected graph G generated from tree T, whi…

链接:https://www.nowcoder.com/acm/contest/140/B来源:牛客网 题目描述 White Rabbit wants to buy some drinks from White Cloud. There are n kinds of drinks, and the price of i-th drink is p[i] yuan per bottle. Since White Cloud is a good friend of White Rabbit, whe…

链接:https://www.nowcoder.com/acm/contest/139/D来源:牛客网 同构图:假设G=(V,E)和G1=(V1,E1)是两个图,如果存在一个双射m:V→V1,使得对所有的x,y∈V均有xy∈E等价于m(x)m(y)∈E1,则称G和G1是同构的,这样的一个映射m称之为一个同构,如果G=G1,则称他为一个自同构. 题目描述 Two undirected simple graphs and where are isomorphic when there exists…

链接:https://www.nowcoder.com/acm/contest/142/G来源:牛客网 The mode of an integer sequence is the value that appears most often. Chiaki has n integers a1,a2,...,an. She woud like to delete exactly m of them such that: the rest integers have only one mode an…

链接:https://www.nowcoder.com/acm/contest/141/J来源:牛客网 Eddy has graduated from college. Currently, he is finding his future job and a place to live. Since Eddy is currently living in Tien-long country, he wants to choose a place inside Tien-long country…

链接:https://www.nowcoder.com/acm/contest/141/A来源:牛客网 Eddy was a contestant participating in ACM ICPC contests. ACM is short for Algorithm, Coding, Math. Since in the ACM contest, the most important knowledge is about algorithm, followed by coding(impl…

链接:https://www.nowcoder.com/acm/contest/141/E来源:牛客网 Eddy likes to play with string which is a sequence of characters. One day, Eddy has played with a string S for a long time and wonders how could make it more enjoyable. Eddy comes up with following…

链接:https://www.nowcoder.com/acm/contest/141/C来源:牛客网 Eddy likes to play cards game since there are always lots of randomness in the game. For most of the cards game, the very first step in the game is shuffling the cards. And, mostly the randomness in…

链接:https://www.nowcoder.com/acm/contest/140/I来源:牛客网 White Cloud has a square of n*n from (1,1) to (n,n). White Rabbit wants to put in several cars. Each car will start moving at the same time and move from one side of one row or one line to the other…

链接:https://www.nowcoder.com/acm/contest/140/D来源:牛客网 White Cloud has built n stores numbered from 1 to n. White Rabbit wants to visit these stores in the order from 1 to n. The store numbered i has a price a[i] representing that White Rabbit can spend…

链接:https://www.nowcoder.com/acm/contest/140/A来源:牛客网 White Cloud is exercising in the playground. White Cloud can walk 1 meters or run k meters per second. Since White Cloud is tired,it can't run for two or more continuous seconds. White Cloud will mo…

链接:https://www.nowcoder.com/acm/contest/139/D来源:牛客网 Two undirected simple graphs and where are isomorphic when there exists a bijection on V satisfying  if and only if {x, y} ∈ E2. Given two graphs and , count the number of graphs satisfying the foll…

链接:https://www.nowcoder.com/acm/contest/141/A 来源:牛客网 题目描述 Eddy was a contestant participating in ACM ICPC contests. ACM is short for Algorithm, Coding, Math. Since in the ACM contest, the most important knowledge is about algorithm, followed by codin…

Removal 链接:https://ac.nowcoder.com/acm/contest/139/E来源:牛客网 题目描述 Bobo has a sequence of integers s1, s2, ..., sn where 1 ≤ si ≤ k. Find out the number of distinct sequences modulo (109+7) after removing exactly m elements. 输入描述: The input consists of…

链接:https://ac.nowcoder.com/acm/contest/148/A 来源:牛客网 Rikka with Lowbit 时间限制:C/C++ 5秒,其他语言10秒 空间限制:C/C++ 262144K,其他语言524288K 64bit IO Format: %lld 题目描述 Today, Rikka is going to learn how to use BIT to solve some simple data structure tasks. While study…

链接:https://ac.nowcoder.com/acm/contest/148/J?&headNav=acm 来源:牛客网 Rikka with Nickname 时间限制:C/C++ 2秒,其他语言4秒 空间限制:C/C++ 262144K,其他语言524288K 64bit IO Format: %lld 题目描述 Sometimes you may want to write a sentence into your nickname like "lubenwei niubi…

题意 n*m的农场有若干种不同种类作物,如果作物接受了不同种类的肥料就会枯萎.现在进行t次施肥,每次对一个矩形区域施某种类的肥料.问最后枯萎的作物是多少. 分析 作者:xseventh链接:https://www.nowcoder.com/discuss/87630?type=101来源:牛客网 我们通过差分(其实就是二维前缀和)可以在O(nm)的时间求出每个点被撒了几次肥料 然后我们可以对每种植物分开求被撒了几次相同种类的肥料,然后判断被撒肥料的次数是否等于被撒的相同种类肥料的次数来确定这个植…

题意 给出一个矩阵,矩阵每行的和必须为2,且是一个主对称矩阵.问你大小为n的这样的合法矩阵有多少个. 分析 作者:美食不可负064链接:https://www.nowcoder.com/discuss/87226?type=101&order=0&pos=1&page=1来源:牛客网 题目给出的合法矩阵是一个类似与邻接矩阵的样式. 所以应该往这方面去考虑. 每行之和等于2 , 代表每个点都连有两条边,可以有重边 不能有自环. 这说明 每个点属于且仅属于一个环. 因为输入只有一个n…

所有牛客多校的做题记录请右转队伍wiki Name Date Rank 2018 Multi-University,Nowcoder Day 1 2018.7.19 16/338 5/10 https://acm.ecnu.edu.cn/wiki/index.php?title=2018_Multi-University,Nowcoder_Day_1 2018 Multi-University,Nowcoder Day 2 2018.7.21 57/338 4/11 https://acm.ec…