A Bounded Storage Algorithm for Copying Cyclic Structures A new algorithm is presented which copies cyclic list structures using bounded workspace and linear time. Unlike a previous similar algorithm, this one makes no assumptions about the storage allocation system in use and uses only operations likely to be available in a high-level language. The distinctive feature of this algorithm is a technique for traversing the structure twice, using the same spanning tree in each case, first from left to right and then from right to left. CACM June, 1977 Robson J. M. copying, shared subtrees, cyclic structures 4.49 5.25 CA770609 JB December 28, 1977 12:56 PM 2766 4 2954 2855 4 2954 2954 4 2954 2954 4 2954 3106 4 2954 3106 4 2954 2665 5 2954 2766 5 2954 2954 5 2954 2954 5 2954 2954 5 2954 3106 5 2954 1549 6 2954 210 6 2954 1972 6 2954 2665 6 2954 2766 6 2954 2855 6 2954 2954 6 2954 2998 6 2954