Inter alia, methods, apparatus, data structures, computer-readable medium, mechanisms, and means for programming routes and access control lists in comparison tree data structures and their use such as in performing lookup operations for use in routers, packet switching systems, and other devices. One implementation identifies a parent node, the parent node including a first node value for indicating a path through a subtree from a root node to the parent node, and the parent node including a first base pointer. A child node of the parent node is added at a memory location based on the base pointer and a next stride value, the child node including a second node value including the first node value and the next stride value.