Source code online books for professionals by professionals

Chapter 4: Induction and Recursion … and Reduction. The three terms in the title are crucial, and they are 
closely related. Here we work with induction and recursion, which are virtually mirror images of each other, both 
for designing new algorithms and for proving correctness. We’ll also take a somewhat briefer look at the idea of 
reduction, which runs as a common thread through almost all algorithmic work.
Chapter 5: Traversal: A Skeleton Key to Algorithmics. Traversal can be understood using the ideas of induction and 
recursion, but it is in many ways a more concrete and specific technique. Several of the algorithms in this book are 
simply augmented traversals, so mastering this idea will give you a real jump start.