树状数组模版（区间更新，区间查询，单点更新，单点查询）

#include 
using namespace std;

#define ll long long
#define mem(a, b) memset(a,b,sizeof(a))
#define INF 0x3f3f3f3f
#define DBG printf("this is a input\n")

//D[i]代表差分数组
ll sum1[500005]; //D[1]+D[2]+D[3]+...+D[i]
ll sum2[500005]; //D[1]+2*D[2]+3*D[3]+...+n*D[n];
int n , m, num[500005];
ll gcd(ll a, ll b) {
    return b == 0 ? a : gcd(b, a % b);
}
ll lcm(ll a, ll b) {
    return a / gcd(a, b) * b;
}

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

void update(int x , int k)//更新区间值
{
    int xi = x;
    while(x <= n)
    {
        //更新系数个k
        sum1[x] += k;
        sum2[x] += k*(xi-1);
        x += lowbit(x);
    }
}

ll get_sum (int x) //1-x的区间和
{
    ll sum= 0;
    int xi = x;
    while(x > 0)
    {
        sum += xi * sum1[x] - sum2[x];
        x -= lowbit(x);
    }
    return sum;
}

int main(void)
{
    mem(num,0);
    mem(sum1,0);
    mem(sum2,0);
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        cin >> num[i];
        update(i, num[i] - num[i - 1]); //构建差分树状数组
    }
    while(m --)
    {
        int z;
        cin>>z;
        if(z == 1)
        {
            int l , r , k;
            cin>>l>>r>>k;
            //区间更新或单点更新
            update(l,k);
            update(r+1,0-k);
        }
        else
        {
            int k;
            cin>>k;
            //区间查询或单点查询
            cout<