There is no pointer to the next node in this case, the node contains data and a delta value.
However, I fail to see how this solves the problem. To find the previous node, I need to know where this and the next node are. Given only this node, however, I can't find the next node.
Therefore, if search and delete are to be done as separate steps, search needs to return a pair of nodes (this and next). My question is, why can't search return a pair of pointers to this and previous, using regular linked list, in the first place?