Task: Text Categorization
Input (English): Sequences of this data structure are used in a data structure created by William Pugh. This data structure was first developed by Allen Newell, Cliff Shaw and Herbert Simon for use in IPL. This is one of the simplest data structures one can build out of conses in Lisp. A dummy object used to simplify boundary conditions in these data structures is called a sentinel. Their "unrolled" type uses the cache to increase performance by storing just enough elements in each section to fill a cache line. Their last element is usually null, but it can reference their first element to form a "circular" one of these data structures. They are often used to implement stacks and queues. These dynamically allocated data structures also come in a "doubly" variety. For 10 points, identify this data structure constructed of nodes with a data field and a pointer to the next node.
Output (English): Science