B - 敌兵布阵

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>

using namespace std;

int sum[50005],a,b;
string s;


int lowbit(int x){
    return x&(-x);
}

void update(int x,int y,int n)
{
    for(int i=x;i<=n;i+=lowbit(i)){
        sum[i]+=y;
    }
}

int getsum(int x){
    int ans=0;
    for(int i=x;i;i-=lowbit(i)){
        ans+=sum[i];
    }
    return ans;
}

int main(){
    int t,k=1;
    cin>>t;
    while(t--){
        cout<<"Case "<<k<<":"<<endl;
        memset(sum,0,sizeof(sum));
        int n;
        cin>>n;
        for(int i=1;i<=n;i++){
            cin>>a;
            update(i,a,n);
        }
        cin>>s;
        while(s!="End"){
            cin>>a>>b;
            if(s=="Add"){
                update(a,b,n);
            }else{
                if(s=="Sub"){
                    update(a,-b,n);
                }else{
                    cout<<getsum(b)-getsum(a-1)<<endl;
                }
            }
            cin>>s;
        }
        k++;
    }
    return 0;
}