Chapter 4. Problem Solving Patterns (new vs old edition)

#1

Hey, I just got the new edition, and I noticed a huge difference in the Problem Solving Patterns presented in both books. I’m not sure which to follow.

The old book had these extra patterns:
Write an equation
Variation
Incremental improvement
Elimination
Parallelism
Caching
Randomization
Approximation
State

Another thing I found very confusing is: in the old book there is a strategy named “Invariants” which is completely different from the “Invariants” strategy described in the new book.
Also in the new book, it seems “Invariants” (from Edition 2) is closer to “Elimination” (from Edition 1), with different problems described.

Please clarify this for me!
Thanks!

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#2

You are on target w your observations.

I wanted to mention we moved caching, parallelism to design problems.

We removed some of the more mathy patterns (eg “write and equation”) after we removed the discrete math and probability chapters.

For elimination, we rolled it in with invariants which can be viewed as generalizing invariants. Incremental improvement was demoted (made more sense as a heuristic - we used to have a chapter on intractable problems, but removed it)

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