Con uently Persistent Deques via Data-Structural Bootstrapping

We introduce data-structural bootstrapping, a technique to design data structures recursively, and use it to design con uently persistent deques. Our data structure requires O(log k) worstcase time and space per deletion, where k is the total number of deque operations, and constant worst-case time and space for other operations. Further, the data structure allows a purely functional implementation, with no side e ects. This improves a previous result of Driscoll, Sleator, and Tarjan. An extended abstract of this paper was presented at the 4th ACM-SIAM Symposium on Discrete Algorithms, 1993. Supported by a Fannie and John Hertz Foundation fellowship, National Science Foundation Grant No. CCR-8920505, and the Center for Discrete Mathematics and Theoretical Computer Science (DIMACS) under NSF-STC88-09648. Also a liated with NEC Research Institute, 4 Independence Way, Princeton, NJ 08540. Research at Princeton University partially supported by the National Science Foundation, Grant No. CCR-8920505, the O ce of Naval Research, Contract No. N00014-91-J-1463, and by DIMACS under NSF-STC88-09648.