Re-implementation of Lock-free Contention Adapting Search Trees Using MRLock

To explore multi-core programming, we re-implement the Lock Free Contention Adapting Search Tree. We follow the structure of the original, using immutable treaps as leaf nodes implemented with an array for better performance with memory caching. The initial re-implementation uses coarse-grained locking with MRLock to provide thread-safety. This will be extended to be lock-free in a future publication.