This chapter and the last have provided examples of the effective use of appropriate data structures with their appropriate implementations. These include the use of a heap for priority queues, the use of a binary tree for a heap, the use of a heap for sorting, and the use of hash tables and binary search trees for searching. Previously we found that trees find numerous applications, ranging from storing data to aiding in the conceptualization of algorithms. Binary trees are not only useful themselves but can serve as the representation for general trees. You have seen that stacks and queues underlie the important tree traversal operations. The virtues and shortcomings of arrays and lists have also been explored.
With respect to problem solving methodology, the top-down approach, with recursion as a special case, has been consistently adhered to. A number of basic strategies have also been illustrated repeatedly. These included searching through the collection of all possible solutions, constructing a solution, and adapting a previously written algorithm to a new but related problem. The rest of this book deals with the same concepts but applies them to more advanced problems.