HDU 1754 I hate it

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #define MMAX 200003
 5 
 6 using namespace std;
 7 int Q[4*MMAX];
 8 int N, F, ql, qr, p, v;
 9 
10 void update(int r, int L, int R)
11 {
12     int M = (L+R)/2;
13     if(L == R)
14         Q[r] = v;
15     else{
16         if(p <= M)
17             update(r*2, L, M);
18         else
19             update(r*2+1, M+1, R);
20         Q[r] = max(Q[r*2], Q[r*2+1]);
21     }
22 }///更新线段树
23 
24 int query(int r,int L,int R)
25 {
26     int ans = -1;
27     int M = (L+R)/2;
28     if(ql <= L && R <= qr)
29         return Q[r];
30     if(qr <= M)
31         return query(r*2, L, M);
32     else if(ql > M)
33         return query(r*2+1, M+1, R);
34     else
35         ans = max(query(r*2, L, M), query(r*2+1, M+1, R));
36     return ans;
37 }///进行区间查询
38 
39 int main()
40 {
41     while(~scanf("%d%d", &N, &F)){
42           //  memset(Q,0,sizeof(Q));
43         for(int i = 0; i < N; i++){
44             scanf("%d", &v);
45             p = i + 1;
46             update(1, 1, N);
47         }
48         for(int i = 0; i < F; i++){
49             char op[5];
50             int a, b;
51             scanf("%s %d %d", op, &a, &b);
52             if(op[0] == ‘Q‘){
53             ql = a, qr = b;
54             printf("%d\n", query(1, 1, N));}
55             else {
56                 p = a, v = b;
57                 update(1, 1, N);
58             }
59         }
60     }
61     return 0;
62 }