hdu 1166 线段树（单点增减 区间求和）

 1 # include <iostream>
 2 # include <cstdio>
 3 # include <cstring>
 4 # include <algorithm>
 5 # include <cmath>
 6 # include <queue>
 7 # define LL long long
 8 using namespace std ;
 9 
10 const int maxn = 50010;
11 
12 int sum[maxn<<2] ; //结点开4倍
13 
14 void PushUP(int rt) //更新到父节点
15 {
16     sum[rt] = sum[rt * 2] + sum[rt * 2 + 1] ; //rt 为当前结点
17 }
18 
19 void build(int l , int r , int rt) //构建线段树
20 {
21     if (l == r)
22     {
23         scanf("%d" , &sum[rt]) ;
24         return ;
25     }
26     int m = (l + r) / 2 ;
27     build(l , m , rt * 2) ;
28     build(m + 1 , r , rt * 2 +1) ;
29     PushUP(rt) ;
30 }
31 
32 void updata(int p , int add , int l , int r , int rt)  //单点增减
33 {
34     if (l == r)
35     {
36         sum[rt] += add ;
37         return ;
38     }
39     int m = (l + r) / 2 ;
40     if (p <= m)
41        updata(p , add , l , m , rt * 2) ;
42     else
43        updata(p , add , m + 1 , r , rt * 2 + 1) ;
44     PushUP(rt) ;
45 }
46 
47 int query(int L , int R , int l , int r , int rt)  //区间求和
48 {
49     if (L <= l && r <= R)
50         return sum[rt] ;
51     int m = (l + r) / 2 ;
52     int ret = 0 ;
53     if (L <= m)
54        ret += query(L , R , l , m , rt * 2) ;
55     if (R > m)
56        ret += query(L , R , m + 1 , r , rt * 2 + 1) ;
57     return ret ;
58 }
59 
60 int main ()
61 {
62     //freopen("in.txt","r",stdin) ;
63     int T  , n;
64     int Case = 0 ;
65     scanf("%d" , &T) ;
66     while (T--)
67     {
68         scanf("%d" , &n) ;
69         build(1 , n , 1) ;
70         char op[10] ;
71         Case++ ;
72         printf("Case %d:\n" , Case) ;
73         while (scanf("%s" , op))
74         {
75             if (op[0] == ‘E‘) //结束
76                break ;
77             int a , b ;
78             scanf("%d %d" , &a , &b) ;
79             if (op[0] == ‘Q‘) //求a,b区间的和
80                printf("%d\n", query(a , b , 1 , n , 1)) ;
81             else if (op[0] == ‘S‘)  //将第a个地方减少b
82                updata(a , -b , 1 , n , 1) ;
83             else if (op[0] == ‘A‘)   //将第a个地方增加b
84                updata(a , b , 1 , n , 1) ;
85         }
86     }
87 
88 
89     return 0 ;
90 }