1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <algorithm>
 4 #include <string.h>
 5 const int N=100010;
 6 using namespace std;
 7 struct node
 8 {
 9     int l,r,sum,minsum,maxsum;
10     int lmax,rmax,lmin,rmin;
11 } Tree[4*N];
12 int a[N];
13 void pushup(int rt)
14 {
15     int l = 2*rt;
16     int r = 2*rt+1;
17     Tree[rt].sum=Tree[l].sum+Tree[r].sum;
18     Tree[rt].minsum=min(min(Tree[l].minsum,Tree[r].minsum),Tree[l].rmin+Tree[r].lmin);
19     Tree[rt].maxsum=max(max(Tree[l].maxsum,Tree[r].maxsum),Tree[l].rmax+Tree[r].lmax);
20     Tree[rt].lmax=max(Tree[l].lmax,Tree[l].sum+Tree[r].lmax);
21     Tree[rt].rmax=max(Tree[r].rmax,Tree[r].sum+Tree[l].rmax);
22     Tree[rt].lmin=min(Tree[l].lmin,Tree[l].sum+Tree[r].lmin);
23     Tree[rt].rmin=min(Tree[r].rmin,Tree[r].sum+Tree[l].rmin);
24 }
25 void build(int l,int r,int rt)
26 {
27     Tree[rt].l = l;
28     Tree[rt].r = r;
29     if (l==r)
30     {
31         Tree[rt].sum=Tree[rt].minsum=Tree[rt].maxsum=a[r];
32         Tree[rt].lmax=Tree[rt].rmax=Tree[rt].lmin=Tree[rt].rmin=a[r];
33         return ;
34     }
35     int mid = (l+r)>>1;
36     build(l,mid,2*rt);
37     build(mid+1,r,2*rt+1);
38     pushup(rt);
39 }
40 void update(int pos,int val,int rt)
41 {
42     if (Tree[rt].l==Tree[rt].r)
43     {
44         Tree[rt].sum=Tree[rt].minsum=Tree[rt].maxsum=val;
45         Tree[rt].lmax=Tree[rt].rmax=Tree[rt].lmin=Tree[rt].rmin=val;
46         return ;
47     }
48     int mid=(Tree[rt].l+Tree[rt].r)>>1;
49     if (pos<=mid)
50         update(pos,val,2*rt);
51     else
52         update(pos,val,2*rt+1);
53     pushup(rt);
54 }
55 int main()
56 {
57     int n,m,pos,val;
58     scanf("%d",&n);
59     for (int i = 1; i <=n; i++)
60     {
61         scanf("%d",&a[i]);
62     }
63     build(1,n,1);
64     scanf("%d",&m);
65     while(m--)
66     {
67         scanf("%d%d",&pos,&val);
68         update(pos,val,1);
69         if(Tree[1].sum==Tree[1].maxsum)
70         {
71             printf("%d\n",Tree[1].sum-Tree[1].minsum);
72         }
73         else
74         {
75             printf("%d\n",max(Tree[1].maxsum,Tree[1].sum-Tree[1].minsum));
76         }
77     }
78     return 0;
79 }