Codeforces 438D The Child and Sequence 给出一个序列,进行如下三种操作: 区间求和 区间每个数模x 单点修改 如果没有第二个操作的话,就是一棵简单的线段树.那么如何处理这个第二个操作呢? 对于一个数a,如果模数 x > a ,则这次取模是没有意义的,直接跳过: 如果 x > a/2 ,则取模结果小于 a / 2; 如果 x < a / 2,取模结果小于x,则也小于 a / 2. 所以对于一个数,最多只会做log a次取模操作.这是可以接受的! 对于一…

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 particular the favorite sequence of Picks. Fortunately, Picks remembers how to repair the sequence. Initi…

在大大推荐下这个标题不明的人做.而我的最后一个非常喜欢的段树,因此,愤怒出手.认为基本上相同.大值,当最大值小于取模时能够剪枝. 今后再遇到此类问题算是能攻克了 // file name: d.cpp // // author: huangjipeng // // creat time: 2014年05月26日 星期一 16时40分18秒 // /////////////////////////////////////////////////////// #include<iostream>…

题意:给定一个n个数的序列,完成以下3个操作: 1.给定区间求和 2.给定区间对x取模 3.单点修改 对一个数取模,这个数至少折半.于是我们记一个最大值max,如果x>max则不做处理. #include<stdio.h> #include<algorithm> using namespace std; #define MAXN 1000000+10 typedef long long LL; ]; int n,m; LL a[MAXN]; void build(int k,…

[原题题面]传送门 [大致题意] 给定一个长度为n的非负整数序列a,你需要支持以下操作: 1:给定l,r,输出a[l]+a[l+1]+…+a[r]. 2:给定l,r,x,将a[l],a[l+1],…,a[r]对x取模. 3:给定k,y,将a[k]修改为y. [数据范围] n,m<=100000,a[i],x,y<=109. [题解大意] 维护最大值和区间和,然后通过最大值有没有超过x来判断需不需要取模操作. [code] #include<bits/stdc++.h> using…

题面 D. The Child and Sequence time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output At the children's day, the child came to Picks's house, and messed his house up. Picks was angry at him. A lot…

传送门 线段树维护区间取模,单点修改,区间求和. 这题老套路了,对一个数来说,每次取模至少让它减少一半,这样每次单点修改对时间复杂度的贡献就是一个log" role="presentation" style="position: relative;">loglog,所以维护区间最大值剪枝,然后每次单点暴力取模,这样的话时间复杂度为O（nlogn）" role="presentation" style="posi…

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 particular the favorite sequence of Picks. Fortunately, Picks remembers how to repair the sequence. Initi…

D. The Child and Sequence time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output 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…

传送门 题目大意: 给你一个序列,要求在序列上维护三个操作: 1)区间求和 2)区间取模 3)单点修改 这里的操作二很讨厌,取模必须模到叶子节点上,否则跑出来肯定是错的.没有操作二就是线段树水题了. 既然必须模到叶子节点,那我们就模咯. 显然,若$b<c$,则$b%c=b$. 因此我们同时维护一个区间最大值,若某区间内最大值小于模数,就把该分支剪掉. 若$a=b%c$,那么肯定有$a \leq \frac{b}{2}$成立. 也就是说,一个数最多被模$\log_2 x$次.总的时间复杂度为$O(…