Mastering Algorithms with Perl

Chapter 3. Advanced Data Structures

Much more often, strategic breakthrough will come from redoing the representation of the data or tables. This is where the heart of a program lies. Show me your flowcharts and conceal your tables, and I shall continue to be mystified. Show me your tables, and I won’t usually need your flowcharts; they’ll be obvious.

—Frederick P. Brooks, Jr., The Mythical Man-Month

There is a dynamic interplay between data structures and algorithms. Just as the right data structure is necessary to make some algorithms possible, the right algorithms are necessary to maintain certain data structures. In this chapter, we’ll explore advanced data structures—structures that are extraordinarily useful, but complex enough to require algorithms of their own to keep them organized.

Despite the versatility of Perl’s hashes and arrays, there are traditional data structures that they cannot emulate so easily. These structures contain interrelated elements that need to be manipulated in carefully prescribed ways. They can be encapsulated in objects for ease of programming, but often only at a high performance cost.

In later chapters, algorithms will take center stage, and the data structures in those chapters will be chosen to fit the algorithm. In this chapter, however, the data structures take center stage. We’ll describe the following advanced data structures:

Linked list

A chain of elements linked together.

Binary tree

A pyramid of elements linked together, each with two ...