HDU 1166 敌兵布阵 （树状数组模板）

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N = 50000+5;
 6 int aa[N];
 7 int c[N];
 8 int n;
 9 int lowbit(int x) {
10     return x&-x;
11 } 
12 
13 void add(int x, int a) {
14     while(x <= n){
15         c[x] += a;
16         x += lowbit(x);
17     }
18 }
19 
20 int sum(int x) {
21     int ans=0;
22     while(x) {
23         ans += c[x];
24         x -= lowbit(x);
25     }
26     return ans;
27 }
28 
29 int main(){
30     int t,a,b,cas;
31     char op[20];
32     scanf("%d",&t);
33     cas=1;
34     while(t--){
35         scanf("%d",&n);
36         memset(c,0,sizeof(c));//WA在了这里 
37         for(int i=1;i<=n;i++){
38             scanf("%d",&aa[i]);
39             add(i, aa[i]);
40         }
41         printf("Case %d:\n",cas++);
42         while(scanf("%s",op),op[0]!=‘E‘){
43             scanf("%d%d",&a,&b);
44                 if(op[0]==‘Q‘){
45                     printf("%d\n",sum(b)-sum(a-1));
46                 }
47                 else if(op[0]==‘S‘)
48                     add(a, -b);
49                 else
50                     add(a, b);
51         }
52     }
53     return 0;
54 }