一个长度为n的数组 每次对lr区间进行修改 如果要修改i 则对i i*2 i*3...都修改 最后单点查询值 思想是利用树状数组维护每一个区间的更新值 查询的时候得出这个点的所有因子的查询值的和 加上这个点的最初值 因为对树状数组理解不深再次错过绝杀... 由于是维护每个点的修改量 所以每次修改 都进行add(l,val) add(r+1,-val) 这时候 如果要求单点的修改值 需要sum(x) 而非sum(x)-sum(x-1) 因为没有将初值进行add 所以c数组存放的其实不是一个前缀和…

题意:给出一个字符串.有两种操作,一个是p a b,问字符串从位置a到位置b的子串是否是一个回文子串.还有一个操作 c a b,把字符串位置a的字符替换为b. 题解:由于字符串长度为1e5且问的次数也有1e5,所以暴力肯定是会超时的,然后考虑用树状数组维护字符串的hash值来解,两个操作分别用正反方向区间比对哈希值和单点改动. #include <cstdio> #include <cstring> #include <algorithm> #define ULL un…

http://acm.timus.ru/problem.aspx?space=1&num=2062 题意:有n个数,有一个值,q个询问,有单点询问操作,也有对于区间[l,r]的每个数i,使得num[i] + w, num[i*2] + w, num[i*3] + w…… 思路:有树状数组和分块两种做法,对比后分块的速度比较快(暴力的艺术).线段树会超时(可能写法不好). 1.树状数组用到的是单点询问区间修改,我要注意一下其写法...修改为:Add(l, w), Add(r + 1, -w); 查…

During several decades, scientists from planet Nibiru are working to create an engine that would allow spacecrafts to fall into hyperspace and move there with superluminal velocity. To check whether their understanding of properties of hyperspace is…

Stars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 8938    Accepted Submission(s): 3551 Problem Description Astronomers often examine star maps where stars are represented by points on a plan…

Stars Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 42898   Accepted: 18664 Description Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a st…

Stars Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 39186 Accepted: 17027 Description Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a star b…

Stars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 4052    Accepted Submission(s): 1592 Problem Description Astronomers often examine star maps where stars are represented by points on a plan…

Stars Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 37323 Accepted: 16278 Description Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a star b…

Stars Description Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a star be an amount of the stars that are not higher and not to the right of the given st…