做的第一道樹狀陣列的題目，模板題。

題目連結

#include<algorithm>
#include<cmath>
#include<cstring>
#include<queue>
#include<iostream>
#include<vector>
#include<map>
#include<cstdio>
#include<cstdlib>
#define ll long long
#define inf 0x3f3f3f3f//1e9+6e7
#define N 50010
#define debug(x) cout<<"X: "<<(x)<<endl
#define de cout<<"**"<<endl
const double pi=acos(-1.0);
using namespace std;

int a[N],c[N],n;

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

void update(int i,int val)
{
    while(i<=n)
    {
        c[i]+=val;
        i+=lowbit(i);
    }
}

int sum(int i)
{
    int ret=0;
    while(i>0)
    {
        ret+=c[i];
        i-=lowbit(i);
    }
    return ret;
}

int main()
{
    int T;
    cin>>T;
    int cas=1;
    char s[100];
    while(T--)
    {
        memset(c,0,sizeof c);
        memset(a,0,sizeof a);
        cin>>n;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
            update(i,a[i]);
        }
        cout<<"Case "<<cas++<<":"<<endl;
        while(scanf("%s",s)&&strcmp(s,"End")!=0)
        {
            int i,j;
            scanf("%d%d",&i,&j);
            if(strcmp(s,"Add")==0)
                {update(i,j);continue;}
            if(strcmp(s,"Sub")==0)
                {update(i,-j);continue;}
            else
            {
                cout<<sum(j)-sum(i-1)<<endl;
            }
        }
    }
    return 0;
}