HDU 1754 I Hate It

 1 #include <bits/stdc++.h>
 2 #define lrt rt<<1
 3 #define rrt rt<<1|1
 4 #define lson l, m, lrt
 5 #define rson m+1, r, rrt
 6 using namespace std;
 7 const int maxn = 200005;
 8 int maxv[maxn<<2];
 9 int n, q;
10 char op[5];
11 
12 void push_up(int rt){
13     maxv[rt] = max(maxv[lrt], maxv[rrt]);
14 }
15 
16 void build(int l, int r, int rt){
17     if (l == r){
18         int num;
19         scanf("%d", &num);
20         maxv[rt] = num;
21         return ;
22     }
23     int m = (l+r)>>1;
24     build(lson);
25     build(rson);
26     push_up(rt);
27 }
28 
29 void modify(int p, int val, int l, int r, int rt){
30     if (l == r){
31         maxv[rt] = val;
32         return ;
33     }
34     int m = (l+r)>>1;
35     if (p <= m)
36         modify(p, val, lson);
37     else
38         modify(p, val, rson);
39     push_up(rt);
40 }
41 
42 int query(int ql, int qr, int l, int r, int rt){
43     if (ql<=l && r<=qr)
44         return maxv[rt];
45     int m = (l+r)>>1;
46     int maxr = 0;
47     if (ql <= m)
48         maxr = max(maxr, query(ql, qr, lson));
49     if (qr > m)
50         maxr = max(maxr, query(ql, qr, rson));
51     return maxr;
52 }
53 
54 int main(){
55     while (~scanf("%d%d", &n, &q)){
56         build(1, n, 1);
57         int a, b;
58         while (q--){
59             scanf("%s%d%d", op, &a, &b);
60             if (op[0] == ‘Q‘)
61                 printf("%d\n", query(a, b, 1, n, 1));
62             else
63                 modify(a, b, 1, n, 1);
64         }
65     }
66     return 0;
67 }