卡常

好好好

#include <iostream> 
#include <vector> 
#include <algorithm> 
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
using namespace std; 
const long long N = 2e5+5; 
vector<long long> a; 
vector<long long> diff_max;  
void preprocess() { 
    diff_max.push_back(0);  
    long long size = a.size();  
    for (long long i = 1; i < size; i++) { 
        long long s = a[i] - a[i - 1]; 
        diff_max.push_back(max(diff_max.back(),  s)); 
    } 
} 
long long s(long long x, long long y, const vector<long long>& pre_sum) { 
    if (y == 1) { 
        return diff_max[x]; 
    } 
    long long m = 0; 
    for (long long i = 1; i <= x; i += y) { 
        long long l = i; 
        long long r = min(i + y - 1, x); 
        long long s = pre_sum[r] - pre_sum[l - 1]; 
        m = max(m, s); 
    } 
    return m; 
}  
int main() { 
    cin.tie(nullptr) -> sync_with_stdio(0);
	cout.tie(nullptr) -> sync_with_stdio(0);
    long long n; 
    cin >> n; 
    a.push_back(0);  
    vector<long long> pre_sum = {0}; 
    long long sum = 0; 
    for (long long i = 0; i < n; i++) { 
        long long num; 
        cin >> num; 
        sum += num; 
        a.push_back(sum);  
        pre_sum.push_back(sum);  
    } 
    preprocess(); 
    long long m; 
    cin >> m; 
    while (m--) { 
        long long x, y; 
        cin >> x; 
        cin >> y; 
        cout << s(x, y, pre_sum) << endl; 
    } 
    return 0; 
}