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
62
63
64
65
66
67
#include <cstdio>
#include <algorithm>
#include <vector>
#include <unordered_map>

using namespace std;
typedef long long ll;

#define MAX 300100

ll S[2*MAX];
ll Sk[2*MAX];
ll Sk0[2*MAX];
ll a[2*MAX];

struct Query {
    int l,r;
};
Query query[MAX];
vector<int> l_pos[MAX];
vector<int> r_pos;

unordered_map<ll, ll> result;

int main() {
    int n,k,q;
    scanf("%d %d %d", &n, &k, &q);
    for(int i=1;i<=n;i++) scanf("%lld", &a[i]);
    for(int i=0;i<q;i++) {
        scanf("%d %d", &query[i].l, &query[i].r);
        if(query[i].r-query[i].l+1>=k) {
            l_pos[query[i].r].push_back(query[i].l);
            r_pos.push_back(query[i].r);
        }
    }
    for(int r=1;r<=n;r++) {
        auto &v = l_pos[r];
        sort(v.begin(),v.end());
        auto last = std::unique(v.begin(), v.end());
        v.erase(last, v.end());
    }
    {
        auto &v = r_pos;
        sort(v.begin(),v.end());
        auto last = std::unique(v.begin(), v.end());
        v.erase(last, v.end());
    }

    for(int i=1;i<=n;i++) S[i]  = S[i-1] + a[i];
    for(int i=1;i<=n-k+1;i++) Sk[i] = S[i+k-1] - S[i-1];

    ll tmp[2*MAX] = {};
    for(int r: r_pos) {
        int min_l = l_pos[r][0];
        for (int l=r+1;l>r-k+1;l--) tmp[l] = 0;
        for (int l=r-k+1;l>=min_l;l--) tmp[l] = max(tmp[l+1],Sk[l]+tmp[l+k]);

        for(int l:l_pos[r]) {
            ll h = (ll(r)<<20) | ll(l);
            result[h]=tmp[l];
        }
    }
    for(int i=0;i<q;i++) {
        ll h = (ll(query[i].r)<<20) | ll(query[i].l);
        printf("%lld\n", result[h]);
    }
}