I'm scratching my head at an output where it would take less time to verify than to just do it yourself. Once you've fully verified you've put in the work required to do it yourself, no?
Also from a computational complexity angle there’s actually a mathematical definition — “NP Complete” which describes problems that are cheap to verify but hard to solve. One example could be a solution to a maze. It’s easy to look at the maze solution and verify it connects start to end without crossing walls, but much more time consuming to actually solve the maze with all the wrong turns needed to produce a solution.