UTEP Computer Science Technical Report UTEP-CS-09-12 Experiments in teaching an engaging and demystifying introduction to algorithms Installment 1: Huffman Codes

As is well known, Huffman’s algorithm is a remarkably simple, and wonderfully illustrative example of how to use the greedy method to design algorithms. However, the Huffman coding problem, which is to find an optimal binary character code (or an optimal binary tree with weighted leaves) is intrinsically technical, and its specification is ill-suited for students with modest mathematical sophistication. This difficulty is circumvented by introducing an alternative precursor problem that is very easy to understand, and where this understanding enables students to use the greedy method to find the solution themselves. The problem is how to merge k sorted lists of varying lengths as efficiently as possible. Once students have solved it, they are better prepared to understand the Huffman coding problem, and why it reduces trivially to the list merging problem they just solved. Even the correctness argument is simplified by this approach.