学步园

#include<cstdio>
#include<cstring>
const int maxn = 50010;
int c[maxn];
int lowbit(int x){
return x&-x;
}
void update(int x,int d){
for(;x<=maxn;x+=lowbit(x))
         c[x]+=d;
}
int query(int x){
int sum=0;
for(;x>0;x-=lowbit(x))
        sum+=c[x];
return sum;
}
int main()
{
int t,n,cases=1,i,j,a,b;
    scanf("%d",&t);
while(t--)
    {
        memset(c,0,sizeof(c));
        scanf("%d",&n);
for(i=1;i<=n;i++)
        {
            scanf("%d",&a);
            update(i,a);
        }
char s[10];
        printf("Case %d:\n",cases++);
while(scanf("%s",s)!=EOF)
        {   
if(!strcmp(s,"End")) break;
else if(!strcmp(s,"Add"))
            {
                scanf("%d%d",&a,&b);
                update(a,b);
            }
else if(!strcmp(s,"Query"))
            {
                scanf("%d%d",&a,&b);
                printf("%d\n",query(b)-query(a-1));
            }
else 
            {
                scanf("%d%d",&a,&b);
                update(a,-b);
            }
        }
    }
return 0;
}