Systems and methods are provided for using an algorithm and data structure for efficient and accurate classification of data items into recovery classes. When a target recovery time (TRT) is specified for a data set, a system may obtain version metadata regarding data items in the data set. The metadata may be obtained in reverse chronological order such that the latest record representing a version or other storage operation is first, followed by the second latest record, and so on. The system may use a bidirectional doubly linked list to efficiently store version data for a particular data item in memory. As version metadata records are read and added to the data structure in reverse chronological order, classification determinations may be triggered when certain conditions are met.