1 #include <cstdio>
 2 #include <iostream>
 3 #include <algorithm>
 4 #include <cstring>
 5 #define MAXNODE 1<<19
 6 using namespace std;
 7 const int MAXN = 2e5+10;
 8 struct data
 9 {
10     int l, r, value;
11 }node[MAXNODE];
12 int score[MAXN];
13 int N, M;
14 
15 void BuildTree(int left, int right, int num)        //建树
16 {
17     node[num].l = left;
18     node[num].r = right;
19     if(left == right)
20     {
21         node[num].value = score[left];
22     }
23     else
24     {
25         BuildTree(left, (left+right)>>1, num<<1); //左子树
26         BuildTree(((left+right)>>1)+1, right, (num<<1)+1); //右子树
27         node[num].value = max(node[num<<1].value, node[(num<<1)+1].value);
28     }
29 }
30 
31 void Update(int stu, int val, int num)    //更新
32 {
33     node[num].value = max(val, node[num].value);
34     if(node[num].l == node[num].r) return;  //更新到叶子结点
35     if(stu <= node[num<<1].r)  Update(stu, val, num<<1);  //更新左子树
36     else Update(stu, val, (num<<1)+1);      //更新右子树
37 }
38 
39 int Query(int left, int right, int num)
40 {
41     if(node[num].l == left && node[num].r == right)  //区间恰好重合
42         return node[num].value;
43     if(right <= node[num<<1].r) //在左子树区间内
44         return Query(left, right, num<<1);
45     if(left >= node[(num<<1)+1].l) //在右子树区间内
46         return Query(left, right, (num<<1)+1);
47     int mid = (node[num].l + node[num].r)>>1;
48     return max(Query(left, mid, num<<1), Query(mid+1, right, (num<<1)+1));
49 }
50 
51 int main()
52 {
53 
54     while(~scanf("%d%d", &N, &M))
55     {
56         for(int i = 1; i <= N; i++)
57             scanf("%d", &score[i]);
58         BuildTree(1, N, 1);
59         char com[3];
60         int a, b;
61         while(M--)
62         {
63             scanf("%s", com);
64             scanf("%d%d", &a, &b);
65             if(com[0] == ‘U‘)
66             {
67                 Update(a, b, 1);
68             }
69             else
70             {
71                 printf("%d\n", Query(a, b, 1));
72             }
73         }
74     }
75     return 0;
76 }