CodeForces 914DBash and a Tough Math Puzzle(线段树的骚操作)
2.5 seconds
256 megabytes
standard input
standard output
Bash likes playing with arrays. He has an array a1, a2, ... an of n integers. He likes to guess the greatest common divisor (gcd) of different segments of the array. Of course, sometimes the guess is not correct. However, Bash will be satisfied if his guess is almost correct.
Suppose he guesses that the gcd of the elements in the range [l, r] of a is x. He considers the guess to be almost correct if he can change at most one element in the segment such that the gcd of the segment is x after making the change. Note that when he guesses, he doesn't actually change the array — he just wonders if the gcd of the segment can be made x. Apart from this, he also sometimes makes changes to the array itself.
Since he can't figure it out himself, Bash wants you to tell him which of his guesses are almost correct. Formally, you have to process qqueries of one of the following forms:
- 1 l r x — Bash guesses that the gcd of the range [l, r] is x. Report if this guess is almost correct.
- 2 i y — Bash sets ai to y.
Note: The array is 1-indexed.
The first line contains an integer n (1 ≤ n ≤ 5·105) — the size of the array.
The second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 109) — the elements of the array.
The third line contains an integer q (1 ≤ q ≤ 4·105) — the number of queries.
The next q lines describe the queries and may have one of the following forms:
- 1 l r x (1 ≤ l ≤ r ≤ n, 1 ≤ x ≤ 109).
- 2 i y (1 ≤ i ≤ n, 1 ≤ y ≤ 109).
Guaranteed, that there is at least one query of first type.
For each query of first type, output "YES" (without quotes) if Bash's guess is almost correct and "NO" (without quotes) otherwise.
- 3
2 6 3
4
1 1 2 2
1 1 3 3
2 1 9
1 1 3 2
- YES
YES
NO
- 5
1 2 3 4 5
6
1 1 4 2
2 3 6
1 1 4 2
1 1 5 2
2 5 10
1 1 5 2
- NO
YES
NO
YES
In the first sample, the array initially is {2, 6, 3}.
For query 1, the first two numbers already have their gcd as 2.
For query 2, we can achieve a gcd of 3 by changing the first element of the array to 3. Note that the changes made during queries of type 1are temporary and do not get reflected in the array.
After query 3, the array is now {9, 6, 3}.
For query 4, no matter which element you change, you cannot get the gcd of the range to be 2.
题意:给出一段序列,两个操作
操作1 给出l,r,x
求区间l-r的gcd,如果至多能改掉区间内的一个数,使gcd是x的倍数,那么输出YES,否则输出NO
操作2 给出pos,x
将序列中pos位置上的数字改为x
题解:我一开始看到这道题,没看到可以修改一个数,然后觉得是一道智障线段树,十分钟不到就写完了,结果非常GG地发现被题意杀了,完了,不会做
后面想了一下,对于返回的一个块,如果他的gcd不是x的倍数,那么这个区间肯定是要改数的,如果这样的区间有两个及以上,那么肯定输出NO
但是我们没法保证如果只有一个块的gcd非x的倍数时,这个块一定只用改一个值
再来考虑,每个块肯定会被分成左块和右块,如果左右两块都不是x的倍数就又GG了
如果只有一个块不是x的倍数,那么就按照上面的思路继续二分这个块
直到二分到只剩下一个数字,此时肯定输出yes
然后就搞定啦~其实还是不难的~
代码如下
- #include<cstdio>
- #include<cstring>
- #include<iostream>
- #include<algorithm>
- #define lson root<<1
- #define rson root<<1|1
- using namespace std;
- int gcd(int a,int b)
- {
- if(b>a)
- {
- swap(a,b);
- }
- if(b)
- {
- return gcd(b,a%b);
- }
- else
- {
- return a;
- }
- }
- int nowson,x,cnt,n,m;
- struct node
- {
- int l,r,g;
- }tr[];
- void push(int root)
- {
- tr[root].g=gcd(tr[rson].g,tr[lson].g);
- }
- void build(int root,int l,int r)
- {
- if(l==r)
- {
- tr[root].l=l;
- tr[root].r=r;
- scanf("%d",&tr[root].g);
- return ;
- }
- int mid=(l+r)>>;
- tr[root].l=l;
- tr[root].r=r;
- build(lson,l,mid);
- build(rson,mid+,r);
- push(root);
- }
- void update(int root,int pos,int v)
- {
- if(tr[root].l==pos&&tr[root].r==pos)
- {
- tr[root].g=v;
- return ;
- }
- int mid=(tr[root].l+tr[root].r)>>;
- if(mid>=pos)
- {
- update(lson,pos,v);
- }
- else
- {
- update(rson,pos,v);
- }
- push(root);
- }
- int query(int root,int l,int r)
- {
- if(tr[root].l==l&&tr[root].r==r)
- {
- if(tr[root].g%x!=)
- {
- cnt--;
- nowson=root;
- }
- return tr[root].g;
- }
- int mid=(tr[root].l+tr[root].r)>>;
- if(l>mid)
- {
- return query(rson,l,r);
- }
- else
- {
- if(r<=mid)
- {
- return query(lson,l,r);
- }
- else
- {
- return gcd(query(lson,l,mid),query(rson,mid+,r));
- }
- }
- }
- int check(int root)
- {
- if(tr[root].l==tr[root].r)
- {
- return ;
- }
- if(tr[lson].g%x!=&&tr[rson].g%x!=)
- {
- return ;
- }
- if(tr[lson].g%x==)
- {
- return check(rson);
- }
- else
- {
- return check(lson);
- }
- }
- int main()
- {
- int n,m;
- scanf("%d",&n);
- build(,,n);
- scanf("%d",&m);
- for(int i=;i<=m;i++)
- {
- int kd,l,r;
- scanf("%d",&kd);
- if(kd==)
- {
- cnt=;
- scanf("%d%d%d",&l,&r,&x);
- int tmp=query(,l,r);
- if(x==tmp)
- {
- puts("YES");
- }
- else
- {
- if((!cnt)&&check(nowson))
- {
- puts("YES");
- }
- else
- {
- puts("NO");
- }
- }
- }
- else
- {
- scanf("%d%d",&l,&r);
- update(,l,r);
- }
- }
- }
CodeForces 914DBash and a Tough Math Puzzle(线段树的骚操作)的更多相关文章
- Codeforces 914D - Bash and a Tough Math Puzzle 线段树,区间GCD
题意: 两个操作, 单点修改 询问一段区间是否能在至多一次修改后,使得区间$GCD$等于$X$ 题解: 正确思路; 线段树维护区间$GCD$,查询$GCD$的时候记录一共访问了多少个$GCD$不被X整 ...
- Codeforces.914D.Bash and a Tough Math Puzzle(线段树)
题目链接 \(Description\) 给定一个序列,两种操作:一是修改一个点的值:二是给一个区间\([l,r]\),问能否只修改一个数使得区间gcd为\(x\). \(Solution\) 想到能 ...
- cf914D. Bash and a Tough Math Puzzle(线段树)
题意 题目链接 Sol 直接在线段树上二分 当左右儿子中的一个不是\(x\)的倍数就继续递归 由于最多递归到一个叶子节点,所以复杂度是对的 开始时在纠结如果一段区间全是\(x\)的两倍是不是需要特判, ...
- CF914D Bash and a Tough Math Puzzle 线段树+gcd??奇怪而精妙
嗯~~,好题... 用线段树维护区间gcd,按如下法则递归:(记题目中猜测的那个数为x,改动次数为tot) 1.若子区间的gcd是x的倍数,不递归: 2.若子区间的gcd是x的倍数,且没有递归到叶子结 ...
- CodeForces 620E New Year Tree(线段树的骚操作第二弹)
The New Year holidays are over, but Resha doesn't want to throw away the New Year tree. He invited h ...
- Bash and a Tough Math Puzzle CodeForces 914D 线段树+gcd数论
Bash and a Tough Math Puzzle CodeForces 914D 线段树+gcd数论 题意 给你一段数,然后小明去猜某一区间内的gcd,这里不一定是准确值,如果在这个区间内改变 ...
- 2018.12.08 codeforces 914D. Bash and a Tough Math Puzzle(线段树)
传送门 线段树辣鸡题. 题意简述:给出一个序列,支持修改其中一个数,以及在允许自行修改某个数的情况下询问区间[l,r][l,r][l,r]的gcdgcdgcd是否可能等于一个给定的数. 看完题就感觉是 ...
- CF 914 D. Bash and a Tough Math Puzzle
D. Bash and a Tough Math Puzzle http://codeforces.com/contest/914/problem/D 题意: 单点修改,每次询问一段l~r区间能否去掉 ...
- D. Bash and a Tough Math Puzzle 解析(線段樹、數論)
Codeforce 914 D. Bash and a Tough Math Puzzle 解析(線段樹.數論) 今天我們來看看CF914D 題目連結 題目 給你一個長度為\(n\)的數列\(a\), ...
随机推荐
- 【BootStrap】 布局组件 II
BootStrap 布局组件 II ■ 分页 BS中通过.pagination的ul元素来实现一个分页集合,一个典型的分页如下: <ul class="pagination" ...
- java设计模式------工厂设计模式
总结 以上就是工厂模式的基本实现和详细说明.包括了简单工厂模式.工厂方法模式.抽象工厂模式.我们可以基于需求来选择合适的工厂模式 基本概念:为创建对象提供过渡接口,以便将创建对象的具体过程屏蔽隔离起来 ...
- 解决NSURLConnection finished with error - code -1100错误
更新到xcode9以后,拖进工程中一个html文件,webview加载这个文件,xcode一直抛出 NSURLConnection finished with error - code -1100异常 ...
- BLESS学习笔记
BLESS全称:Bloom-filter-based Error Correction Solution for High-throughput Sequencing Reads,即基于布隆过滤器的高 ...
- 漫谈Java IO之普通IO流与BIO服务器
今天来复习一下基础IO,也就是最普通的IO. 网络IO的基本知识与概念 普通IO以及BIO服务器 NIO的使用与服务器Hello world Netty的使用与服务器Hello world 输入流与输 ...
- [日常] 最近的一些破事w...
更新博文一篇以示诈尸(大雾 (其实只是断了个网然后就彻底失踪了一波w...连题解都没法写了QAQ) $ \tiny{诈尸的实际情况是老姚提前走还把十一机房门锁了然而钥匙在联赛的时候就还了于是并不能进去 ...
- 【福大软工】 W班级总成绩排名2
评分链接: 选题报告 结对第二次作业 需求分析 随堂测试 总分排名:
- Beta第一天
听说
- 2017-2018-1 1623 bug终结者 冲刺001
bug终结者 冲刺001 冲刺阶段任务分配 任务 工作量比例 完成时间 负责人 第一篇博客:各个成员的任务安排 1/7 12月1日 20162322 朱娅霖 第二篇博客:欢迎界面,主菜单界面 1/7 ...
- scrapy crawl 源码修改 爬虫多开
import os from scrapy.commands import ScrapyCommand from scrapy.utils.conf import arglist_to_dict fr ...