萌新样例没过，求调

#include <iostream>
#define int long long
using namespace std;
const int N = (int)2e5 + 10; 

int n, m, a[N];
struct segtree{
    int l, r, num, lazy;
}tr[4*N];
void pushup(int i){
    tr[i].num = tr[i << 1].num + tr[i << 1 | 1].num;
}
void build(int i, int l, int r){
    tr[i].l = l;
    tr[i].r = r;
    tr[i].lazy = 0;
    if (l == r){
        tr[i].num = a[i];
        return;
    }

    int mid = (l + r) >> 1;
    build(i << 1, l, mid);
    build(i << 1 | 1, mid + 1, r);
    pushup(i);
}
void f(int i, int l, int r, int k){
    tr[i].lazy += k;
    tr[i].num += k * (r - l + 1);
}
void pushdown(int i, int l, int r){
    if (tr[i].lazy){
        int mid = (l + r) >> 1;
        f(i << 1, l, mid, tr[i].lazy);
        f(i << 1 | 1, mid + 1, r, tr[i].lazy);
        tr[i].lazy = 0;
    }
}
void modify(int i, int l, int r, int ql, int qr, int k){
    if (ql <= l && qr >= r){
        f(i, l, r, k);
        return;
    }
    pushdown(i, l, r);
    int mid = (l + r) >> 1;
    if (ql <= mid) modify(i << 1, l, mid, ql, qr, k);
    if (qr > mid) modify(i << 1 | 1, mid + 1, r, ql, qr, k);
    pushup(i);
}
int query(int i, int l, int r, int ql, int qr){
    int ret = 0;
    if (ql <= l && qr >= r){
        return tr[i].num;
    }
    int mid = (l + r) >> 1;
    pushdown(i, l, r);
    if (ql <= mid) ret += query(i << 1, l, mid, ql, qr);
    if (qr > mid) ret += query(i << 1 | 1, mid + 1, r, ql, qr);

    return ret;
}
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int op, x, y, k;

    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> a[i];
    build (1, 1, n);
    for (int i = 1; i <= m; i++){
        cin >> op;
        if (op == 1){
            cin >> x >> y >> k;
            modify(1, 1, n, x, y, k);
        }else{
            cin >> x >> y;
            cout << query(1, 1, n, x, y) << endl;
        }
    }

    return 0;
}

我的输出：

3
5
11

样例输出：

11
8
20

调了好久都没发现问题在哪……