clrs; exercise 10.2.1 - O(1) singly linked INSERT & DELETE
clrs; exercise 10.2.2 - stack via singly linked list
clrs; exercise 10.2.3 - queue via singly linked list
clrs; exercise 10.2.4 - one-test LIST-SEARCH'
clrs; exercise 10.2.5 - set via circular list
clrs; exercise 10.2.6 - UNION in O(1)
clrs; exercise 10.2.7 - reverse in constant space
clrs; exercise 10.2.8 - XOR doubly linked list