Does a flight cycle require a minimum duration? For medium/long-haul pressurized airliners that are used on short routes.

How is a cycle calculated?

Wouldn't the short flights impact the maintenance schedule due to the frequency of pressurization cycles?
Much of the wear on an engine happens during startup, so while yes it does have a significant impact on maintenance costs, it's rather unavoidable unless the operator chooses to avoid shutdown between flights (as some do, e.g. skydiving and ag spraying)