HDU1166敌兵布阵（树状数组-单点更新+区间查询）

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#include<bits/stdc++.h>
using namespace std;
#define pi acos(-1)
#define mod 998244353
#define INF 0x3f3f3f
#define fi first
#define se second
#define it iterator
#define ins insert
#define mp make_pair
#define pb push_back
#define ll long long
#define ull unsigned long long
#define mem(a) memset(a,0,sizeof(a))
#define cio ios::sync_with_stdio(false)
#define gcd __gcd
ll lgcd(ll a,ll b){return b == 0? a:lgcd(b, a % b);}
int lowbit(int x){return x&(-x);}
#define T int t;scanf("%d",&t);while(t--)
#define CE cout << endl
#define C(n) cout << n << endl
#define CY cout << "YES" << endl
#define CN cout << "NO" << endl
#define Cy cout << "Yes" << endl
#define Cn cout << "No" << endl

int a[50010];
int c[50010];

void update(int x, int y, int n) // x为更新的位置，y为在a[x]的基础上+y，n为数组的大小
{
    for(int i = x; i <= n; i += lowbit(i)){
        c[i] += y;
    }
}
int getsum(int x)  // 区间查询
{
    int ans = 0;
    for(int i = x; i; i -= lowbit(i)){
        ans += c[i];
    }
    return ans;
}

int main()
{
    int cnt = 1;
    T{
        mem(a);
        mem(c);
        cout << "Case " << cnt++ << ":" << endl;
        int n;
        cin >> n;
        for(int i = 1; i <= n; i++){
            cin >> a[i];
            update(i,a[i],n);  // 初始化树状数组
        }
        string q;
        while(cin>>q){
            if(q=="End") break;
            int x, y;
            cin >> x >> y;
            if(q=="Add"){
                update(x,y,n);   // 单点更新（加上x）
            }else if(q=="Sub"){
                update(x,-y,n);  // 单点更新（减去y）
            }else{
                C(getsum(y)-getsum(x-1)); // 求区间x-y
            }
        }
    }
    return 0;   
}