1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
#include <bits/stdc++.h>

using namespace std;

int n, k, q;
long long skill[300002];
struct hash_pair
{
    size_t operator() (const pair<int, int> &pair) const {
        return hash<int>()(pair.first) ^ hash<int>()(pair.second);
    }
};

vector<long long> best;
unordered_map< pair<int, int>, int, hash_pair> range_to_idx;
vector< pair<int, int>> ranges;
long long result[300002];
long long prefix[300002];


int main() {

    cin >> n >> k >> q;
    for (int i = 1; i <= n; i++) {
        cin >> skill[i];
        prefix[i] = prefix[i-1] + skill[i];
    }

    for (int i = 1; i <= q; i++) {
        int l, r;
        cin >> l >> r;
        ranges.push_back({l, r});
        range_to_idx[{l, r}] = i;
    }
    sort(ranges.begin(), ranges.end());
    //for (auto range : ranges)
    //    cout << range.first << " " << range.second << endl;
    int curr_first = 0;
    for (auto range : ranges) {
        if (curr_first < range.first) {
            best.clear();
            curr_first = range.first;
        }
        if (range.second - range.first < k - 1) {
            result[range_to_idx[range]] = 0;
            continue;
        }
        int pos = range.first + k - 1 + best.size();
        while (pos <= range.second) {
            //cout << "POS: " << pos << endl;
            long long range_sum = prefix[pos] - prefix[pos - k];
            best.push_back(max((!best.empty()) ? best.back() : 0, range_sum + ( (best.size() < k) ? 0 : best[best.size() - k])));
            pos++;
        }
        result[range_to_idx[range]] = (!best.empty()) ? best.back() : 0;
    }
    for (int i = 1; i <= q; i++) {
        cout << result[i] << endl;
    }
    return 0;
}