1 #include<cstdio>
2 #include<algorithm>
3 #include<string.h>
4 #include<math.h>
5 #include<queue>
6 #include<iostream>
7 using namespace std;
8 const int maxn=2e5+10;
9 int ary[maxn];
10 struct node
11 {
12 int l,r,val;
13 }tree[maxn<<2];
14 void push_up(int cur)
15 {
16 tree[cur].val=max(tree[cur*2].val,tree[cur*2+1].val);
17 }
18 void build(int l,int r,int cur)
19 {
20 tree[cur].l=l,tree[cur].r=r;
21 tree[cur].val=0;
22 if(l==r){
23 tree[cur].val=ary[l];
24 return;
25 }
26 int mid=(l+r)/2;
27 build(l,mid,cur*2);
28 build(mid+1,r,cur*2+1);
29 push_up(cur);
30 }
31 int query(int l,int r,int cur)
32 {
33
34 if(l<=tree[cur].l&&r>=tree[cur].r)
35 return tree[cur].val;
36 int mid=(tree[cur].l+tree[cur].r)/2;
37 int ans=0;
38 if(l<=mid) ans=max(ans,query(l,r,cur*2));
39 if(r>mid) ans=max(ans,query(l,r,cur*2+1));
40 return ans;
41 }
42 void Update(int base,int price,int cur)
43 {
44 if(tree[cur].l==tree[cur].r){
45 tree[cur].val=price;
46 return;
47 }
48 int mid=(tree[cur].l+tree[cur].r)/2;
49 if(base<=mid) Update(base,price,cur*2);
50 else Update(base,price,cur*2+1);
51 push_up(cur);
52 }
53 int main()
54 {
55 int n,m;
56 while(scanf("%d%d",&n,&m)!=EOF){
57 for(int i=1;i<=n;i++) scanf("%d",&ary[i]);
58 build(1,n,1);
59 while(m--){
60 char tmp;
61 cin>>tmp;
62 if(tmp=='Q'){
63 int l,r;
64 scanf("%d%d",&l,&r);
65 int ans=query(l,r,1);
66 printf("%d\n",ans);
67 }
68 else{
69 int l,r;
70 scanf("%d%d",&l,&r);
71 Update(l,r,1);
72 }
73 }
74 }
75 return 0;
76 }
