1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 
 5 using namespace std;
 6 
 7 struct node
 8 {
 9     int l,r;
10     int score;
11 } s[200000*4+10];
12 
13 void InitTree(int l,int r,int k)
14 {
15     s[k].l=l;
16     s[k].r=r;
17     s[k].score=0;
18     if (l==r)
19         return ;
20     int mid=(l+r)/2;
21     InitTree(l,mid,k*2);
22     InitTree(mid+1,r,2*k+1);
23 }
24 
25 
26 void UpdataTree(int i,int ad,int k)
27 {
28     if (s[k].l==s[k].r&&s[k].r==i)
29     {
30         s[k].score=ad;
31         return ;
32     }
33     int mid=(s[k].l+s[k].r)/2;
34     if (i<=mid)
35     {
36         UpdataTree(i,ad,k*2);
37     }
38     else if (i>mid)
39     {
40         UpdataTree(i,ad,k*2+1);
41     }
42     s[k].score=s[k*2].score>s[k*2+1].score?s[k*2].score:s[k*2+1].score;
43 }
44 
45 int sum;
46 
47 int SearchTree(int st,int e,int k)
48 {
49     if (st==s[k].l&&e==s[k].r)
50     {
51         return s[k].score;
52     }
53     int mid=(s[k].l+s[k].r)/2;
54     if (e<=mid)
55         return SearchTree(st,e,k*2);
56     else if (st>mid)
57         return SearchTree(st,e,k*2+1);
58     else
59     {
60         int a=SearchTree(st,mid,2*k);
61         int b=SearchTree(mid+1,e,2*k+1);
62         return a>b?a:b;
63     }
64 }
65 
66 int main ()
67 {
68     int n,m,a,x,y,ans;
69     char ch;
70     while (~scanf("%d%d",&n,&m))
71     {
72         sum=0;
73         InitTree(1,n,1);
74         for (int i=1; i<=n; i++)
75         {
76             scanf("%d",&a);
77             UpdataTree(i,a,1);
78         }
79         for (int i=1; i<=m; i++)
80         {
81             getchar();
82             scanf("%c",&ch);
83             if (ch==‘Q‘)
84             {
85                 scanf("%d%d",&x,&y);
86                 ans=SearchTree(x,y,1);
87                 printf ("%d\n",ans);
88             }
89             else if (ch==‘U‘)
90             {
91                 scanf("%d%d",&x,&y);
92                 UpdataTree(x,y,1);
93             }
94         }
95     }
96     return 0;
97 }