> (In case you were wondering, the _real_ answer I'm hoping for is "I'd ask Google Maps." I've had exactly two people give me this response in the 8+ years I've been giving this challenge. I don't know if it's because they think it's a dumb answer, if they know that I expect a code-related answer, or if it never occurs to them... but I like to think someone who wants to see what Google says isn't the type that constantly wants to reinvent the wheel. Note that NOT giving this answer is not a deal-breaker. I generally give the benefit of the doubt to candidates here.)

I'm surprised that this rarely seems to be brought up as a solution. It was the first approach I had in mind since you really can't split and format all those potentially mistyped addresses reliably without looking them up in a database/directory of valid addresses.

It feels very obvious, however admittedly in an interview situation I might actually assume that the interviewer doesn't want me to use the third-party look up approach as it feels like cheating, which is somewhat absurd since it's the correct approach.