rt，这个方法为什么不对

ll query(int x, int l, int r, int L, int R, ll add) {
	if(L <= l && r <= R) return t[x].sum + t[x].sz * add;
	int mid = l + r >> 1;
	ll ret = 0;
	if(mid >= L) ret += query(t[x].l, l, mid, L, R, add + t[x].tag);
	if(mid < R) ret += query(t[x].r, mid + 1, r, L, R, add + t[x].tag);
	return ret;
}