GSS

 库存

GSS1

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long LL;
 4 
 5 inline int read() {
 6     int x=0,f=1;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-1;
 7     for (;isdigit(ch);ch=getchar())x=x*10+ch-'0';return x*f;
 8 }
 9 
10 const int N = 100100;
11 struct Seg{
12     int S,LS,RS,sum;
13 }T[N<<2];
14 
15 #define Root 1,n,1
16 #define lson l,mid,rt<<1
17 #define rson mid+1,r,rt<<1|1
18 
19 void pushup(int rt) {
20     T[rt].sum = T[rt<<1].sum + T[rt<<1|1].sum;
21     T[rt].LS = max(T[rt<<1].LS,T[rt<<1].sum+T[rt<<1|1].LS);
22     T[rt].RS = max(T[rt<<1|1].RS,T[rt<<1|1].sum+T[rt<<1].RS);
23     T[rt].S = max(T[rt<<1].RS+T[rt<<1|1].LS,max(T[rt<<1].S,T[rt<<1|1].S));
24 }
25 void build(int l,int r,int rt) {
26     if (l == r) {
27         T[rt].S = T[rt].LS = T[rt].RS = T[rt].sum = read();
28         return ;
29     }
30     int mid = (l + r) >> 1;
31     build(lson);
32     build(rson);
33     pushup(rt);
34 }
35 Seg query(int l,int r,int rt,int L,int R) {
36     if (L <= l && r <= R) {
37         return T[rt];
38     }
39     int mid = (l + r) >> 1;
40     if (L <= mid && R > mid) {
41         Seg res,ll,rr;
42         ll = query(lson,L,R);rr = query(rson,L,R);
43         res.sum = ll.sum + rr.sum;
44         res.LS = max(ll.LS,ll.sum+rr.LS);
45         res.RS = max(rr.RS,rr.sum+ll.RS);
46         res.S = max(ll.RS+rr.LS,max(ll.S,rr.S));
47         return res;
48     }
49     else if (L <= mid) return query(lson,L,R);
50     else if (R > mid) return query(rson,L,R);    
51 }
52 
53 int main() {
54     int n = read();
55     build(Root);
56     int m = read();
57     while (m--) {
58         int l = read(),r = read();
59         Seg ans = query(Root,l,r);
60         printf("%d\n",ans.S);
61     }
62     return 0;
63 }

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