如果你的样例不过

void update(int &p,int rt,int l,int r,int x,ll v){
	if(!p) p = ++cnt;
  //z[p] = z[rt]; z[p].sum += v; 显然不对
	z[p].sum = z[rt].sum + v; 
	if(l == r) return;
	if(x <= mid) z[p].rs = z[rt].rs, update(z[p].ls,z[rt].ls,l,mid,x,v);
	else z[p].ls = z[rt].ls, update(z[p].rs,z[rt].rs,mid+1,r,x,v);
}