the super cute girl's arm was contiguous with the boy's arm, and he was very excited about it.

malloc or calloc

Contiguous means touching. Alaska is not one of the contiguous states.

"is my disease contiguous

My research shows that usage of "contiguous to" has greatly exceeded "contiguous with" for several centuries until relatively recently. Usage of "contiguous to" still exceeds "contiguous with," but by a very narrow margin. Try plugging these into a Google n-gram and you'll see the usage history since 1800.