Puzzles for Programmers and Pros

Part II: The Secret of the Puzzle

Ravi, Prasad, and I are working together still at the same software company. The founding partners of our company are always raving about how great it was to have recruited from the heuristics class.

—from a graduate of the Heuristic Problem Solving class at New York University

Part of the charm of puzzles is that they escape formulaic solutions. I often encounter students who do very well in calculus and discrete mathematics but find themselves stumped by puzzles whose reasoning requires only the most elementary algebra. Creativity is not the issue. Some people find the freedom offered by puzzles unfamiliar, and even slightly frightening. In this chapter, together, we will exorcise that fear demon.

The best puzzles may appear impossible at first, until you break them down, try alternatives, and finally solve them. The fact that a similar process is necessary in all large engineering and software projects is one reason that puzzles are used to screen job candidates. (A competing theory is that interviewers use puzzles to see people squirm. I'm not denying there is a little of that.)

If you had asked me a few years ago how to improve your puzzle-solving abilities, I would have recommended trying a lot of puzzles until you understood the patterns. But I've come to realize that certain patterns can be taught and their role in puzzles exposed. I've taught a class at New York University based on that belief, and it seems not only to hold, but also ...