There is already a different (more useful) algorithm called ternary search (http://en.wikipedia.org/wiki/Ternary_search).

Both I and my wife have a tendency to call her tricycle a "bike" or "bicycle", and to ride on roads expressly marked as bicycle lanes.

Many physically disabled people ride tricycles. Don't know about the GP's wife but it's a good thing to keep in mind. Could prevent you from possibly making some painfully unfunny jokes.

She bought it because she likes it over a regular bicycle.

Just to add, there can also be commercial reasons for a tricycle. In my neighborhood growing up in Miami, there was an ice cream vendor and a knife grinder who went around on trikes. In the latter case, the chain was switched over to the grinding stone to provide power.

There are plenty of reasons a person might find a tricycle more appropriate for their use than a bicycle, personal preference of course being a perfectly reasonable one.

That being my wife's reason. She fell in love with recumbents in college, after trying one that a professor had, and bought a Hase Lepus Comfort recumbent tricycle a few years ago. She likes the stability, being close to the ground, sitting on a real seat instead of a saddle, and the cargo space for groceries or camping gear.

Probably poor joke aside, I'd never heard of adults riding tricycles, so thanks in any case for the informative answers.