Turtles (非纯分块)

http://codeforces.com/contest/103/problem/D

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define faster ios::sync_with_stdio(0);cin.tie(0)

inline ll read()
{
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}

/********************************************************************/

const int maxn = 3e5+5;
ll n, m;
ll a[maxn];
ll cx[maxn], cy[maxn];
int kiss = 600;
vector<int> d[600];
ll dp[maxn];
ll ans[maxn];

int main(){
    n = read();
    for(int i = 1;i <= n;i++)
        a[i] = read();
    m = read();
    for(int i = 1;i <= m;i++){
        cx[i] = read(), cy[i] = read();
        if(cy[i] < kiss)
            d[cy[i]].push_back(i);
        else{
            ll ans1 = 0;
            for(int j = cx[i];j <= n;j += cy[i]){
                ans1 += a[j];
            }
            ans[i] = ans1;
        }
    }
    for(int i= 1;i < kiss;i++){
        if(d[i].size()){
            for(int j = n;j;j--){       //From the back forward
                if(j+i > n)
                    dp[j] = a[j];
                else
                    dp[j] = dp[j+i] + a[j];
            }
            for(int j = 0;j < d[i].size();j++)
                ans[d[i][j]] = dp[cx[d[i][j]]];
        }
    }
    for(int i = 1;i <= m;i++)
        cout << ans[i] << endl;
    return 0;
}