Discription

As you know, the most intelligent beings on the Earth are, of course, cows. This conclusion was reached long ago by the Martian aliens, as well as a number of other intelligent civilizations from outer space.

Sometimes cows gather into cowavans. This seems to be seasonal. But at this time the cows become passive and react poorly to external stimuli. A cowavan is a perfect target for the Martian scientific saucer, it's time for large-scale abductions, or, as the Martians say, raids. Simply put, a cowavan is a set of cows in a row.

If we number all cows in the cowavan with positive integers from 1 to n, then we can formalize the popular model of abduction, known as the (a, b)-Cowavan Raid: first they steal a cow number a, then number a + b, then — number a + 2·b, and so on, until the number of an abducted cow exceeds n. During one raid the cows are not renumbered.

The aliens would be happy to place all the cows on board of their hospitable ship, but unfortunately, the amount of cargo space is very, very limited. The researchers, knowing the mass of each cow in the cowavan, made p scenarios of the (a, b)-raid. Now they want to identify the following thing for each scenario individually: what total mass of pure beef will get on board of the ship. All the scenarios are independent, in the process of performing the calculations the cows are not being stolen.

Input

The first line contains the only positive integer n (1 ≤ n ≤ 3·105) — the number of cows in the cowavan.

The second number contains n positive integer wi, separated by spaces, where the i-th number describes the mass of the i-th cow in the cowavan (1 ≤ wi ≤ 109).

The third line contains the only positive integer p — the number of scenarios of (a, b)-raids (1 ≤ p ≤ 3·105).

Each following line contains integer parameters a and b of the corresponding scenario (1 ≤ a, b ≤ n).

Output

Print for each scenario of the (a, b)-raid the total mass of cows, that can be stolen using only this scenario.

Please, do not use the %lld specificator to read or write 64-bit integers in С++. It is recommended to use the cin, cout streams of the %I64d specificator.

Examples

Input
3
1 2 3
2
1 1
1 2
Output
6
4
Input
4
2 3 5 7
3
1 3
2 3
2 2
Output
9
3
10 比较显然的是对b 分块: b大的直接暴力算; b小的时候之前预处理一下然后直接回答询问。。。。
但是看了一下空间限制。。。。。70M。。。。这就只能开 300000 * 30 的 long long 啊。。。突然感觉分块大失败。
不过问题并不在这里,因为我们完全可以离线做, b >=sqrt(N) 的询问直接回答;b<=sqrt(N) 的询问先记下来, 然后我们再跑 sqrt(N) 次查找,每次处理出 步长为i, 从每个位置向后能够得到的牛个数。 这样一遍就是O(N) 的。。
于是总的复杂度就是 O(N * sqrt(N) + Σ [b>sqer(N)] * (N/b))
#include<bits/stdc++.h>
#define ll long long
#define pb push_back
using namespace std;
const int maxn=300005;
const int Base=550;
struct node{ int num,B;};
vector<node> g[Base+5];
ll ans[maxn],f[maxn];
int n,a[maxn],Q; inline int read(){
int x=0; char ch=getchar();
for(;!isdigit(ch);ch=getchar());
for(;isdigit(ch);ch=getchar()) x=x*10+ch-'0';
return x;
}
void W(ll x){ if(x>=10) W(x/10); putchar(x%10+'0');} inline void solve(){
node x;
for(int i=1;i<=Base;i++) if(g[i].size()){
memset(f,0,sizeof(f));
for(int j=n;j;j--) f[j]=a[j]+(ll)(j+i<=n?f[j+i]:0);
for(int j=g[i].size()-1;j>=0;j--){
x=g[i][j];
ans[x.num]=f[x.B];
}
}
} int main(){
// freopen("data.in","r",stdin);
// freopen("data.out","w",stdout); n=read();
for(int i=1;i<=n;i++) a[i]=read(); Q=read(); int S,T;
for(int i=1;i<=Q;i++){
S=read(),T=read();
if(T<=Base) g[T].pb((node){i,S});
else for(int j=S;j<=n;j+=T) ans[i]+=(ll)a[j];
} solve(); for(int i=1;i<=Q;i++) W(ans[i]),puts("");
return 0;
}

  

 

CodeForces - 103D Time to Raid Cowavans的更多相关文章

  1. CodeForces 103D Time to Raid Cowavans 询问分块

    Time to Raid Cowavans 题意: 询问 下标满足 a + b * k 的和是多少. 题解: 将询问分块. 将b >= blo直接算出答案. 否则存下来. 存下来之后,对于每个b ...

  2. CodeForces 103D Time to Raid Cowavans 分块+dp

    先对b从小到大sort,判断b是不是比sqrt(n)大,是的话就直接暴力,不是的话就用dp维护一下 dp[i]表示以nb为等差,i为起点的答案,可以节省nb相同的情况 #include<bits ...

  3. Codeforces Beta Round #80 (Div. 1 Only) D. Time to Raid Cowavans 离线+分块

    题目链接: http://codeforces.com/contest/103/problem/D D. Time to Raid Cowavans time limit per test:4 sec ...

  4. CodeForces 103 D Time to Raid Cowavans

    Time to Raid Cowavans 题意:一共有n头牛, 每头牛有一个重量,m次询问, 每次询问有a,b 求出 a,a+b,a+2b的牛的重量和. 题解:对于m次询问,b>sqrt(n) ...

  5. Codeforces103D - Time to Raid Cowavans

    Portal Description 给出长度为\(n(n\leq3\times10^5)\)的序列\(\{a_n\}\),进行\(q(q\leq3\times10^5)\)次询问:给出\(x,y\) ...

  6. (分块暴力)Time to Raid Cowavans CodeForces - 103D

    题意 给你一段长度为n(1 ≤ n ≤ 3·1e5)的序列,m (1 ≤ p ≤ 3·1e5)个询问,每次询问a,a+b,a+2b+...<=n的和 思路 一开始一直想也想不到怎么分,去维护哪些 ...

  7. Codeforces Beta Round #80 (Div. 1 Only) D. Time to Raid Cowavans 分块

    D. Turtles Time Limit: 20 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/103/problem/D ...

  8. CodeForces 103D 分块处理

    题目链接:http://codeforces.com/problemset/problem/103/D 题意:给定一个长度为n的序列.然后q个询问.每个询问为(a,b),表示从序列第a项开始每b项的加 ...

  9. D. Time to Raid Cowavans 分块暴力,感觉关键在dp

    http://codeforces.com/contest/103/problem/D 对于b大于 sqrt(n)的,暴力处理的话,那么算出每个的复杂度是sqrt(n),就是把n分成了sqrt(n)段 ...

随机推荐

  1. vba中ListBox控件的使用

    给ListBox添加内容 If CheckBox8 = True Then---------------------------checkbox控件被选中 For i = 0 To ListBox1. ...

  2. 关于前后端日期处理 开发注意事项 jquery.tmpl()函数的使用

    1当后端将日期传到前段的时候 我们通常会需要将日期转为制定格式 除了平常我们使用的前段插件将日期转好 spring @datetimeFormat 注解 这些形式外 我们还可以在实体里通过get方法进 ...

  3. java的类加载器体系结构和双亲委派机制

    类加载器将字节码文件加载到内存中,同时在方法区中生成对应的java.land.class对象  作为外部访问方法区的入口. 类加载器的层次结构: 引导类加载器<-------------扩展类加 ...

  4. 极简Node教程-七天从小白变大神(一:你需要Express)

    如果说用一句话来概括Node那就是:它开启了JavaScript服务器端语言. Node系列的文章并不会从一开始长篇概论的讲Node的历史,安装,以及其他很琐碎的事情.只会专门介绍关于Node或者准确 ...

  5. Python+Selenium练习篇之21-如何截图并保存

    本文介绍如何利用Selenium的方法进行截图,在测试过程中,是有必要截图,特别是遇到错误的时候进行截图.在selenium for python中主要有三个截图方法,我们挑选其中最常用的一种. ge ...

  6. day02_05.除数与被除数

    第5题 除数与被除数 编程需要一定数学能力,在这看看你找到了几个有用条件, 又该如何来运用他们呢? 学习是互通的 题目:两个自然数相除,商3余10,被除数,除数,商,余数的和是163,求被除数,除数. ...

  7. sqlserver 取时间段重复或者不重复的数据

    declare @str datetime, @end datetime select @str='2013-04-05',@end='2013-04-10'select * from arp_hbs ...

  8. [oldboy-django][2深入django]django一个请求的生命周期 + WSGI + 中间件

    1 WSGI # WSGI(是一套协议,很多东西比如wsgiref, uwsgiref遵循这一套协议) - django系统本质 别人的socket(wsgiref或者uwsgiref) + djan ...

  9. HDU 2440、HDU 3694多边形费马点

    1.http://acm.hdu.edu.cn/showproblem.php?pid=2440   按照题意知道是一个简单的多边形即凸包,但给出的点并没有按照顺序的,所以需要自己先求出凸包,然后在用 ...

  10. spring+xml集成测试(准备数据和验证项的外部文件化)

    Spring的集成测试 单位测试和集成测试,我想大家都做过,一般情况下,一般逻辑且不需要操作数据库的情况比较适合于单位测试了.而对于一个数据库应用来说,集成测试可能比单元测试更重要,你可以想象,一个互 ...