[lhorie]

I'd ask you to reconsider what an optimization is, and to also consider the concept of "premature cleverification".

A switch statement is a pretty idiomatic choice for the example. Merely knowing more about the low level cost of different options does not make a snippet an optimization.

Examples of actual optimizations (from real world code I've seen) would include using bitmaps, lookup tables, large regexps, tries and binary search. All of these have the property of obscuring the search space in the name of performance, and many come with trade-offs such as increased startup cost or code size. Choosing to use a trie here, for example, without considering its trade offs would be a premature optimization. A switch statement is at worst a refactor that maintains the same algorithm.