This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
There are a couple of basic underlying structures you can use for a list, depending on how it is to be used. One is easy to access elements with an index and the other is more efficient for inserting elements into the middle of the list. The required methods in the question points toward one of these structures, do you know which one and what it is?