I checked out the Gold Mine problem on geeksforgeeks (assuming it is the same problem at firebase). Can you explain why it is "potentially impossible" to get the optimal solution?
I figure it hasn't been used for recruiting in a long time, so there shouldn't be any downside of that nature to it being so. But there is the invested time in making it available, of course.
I hardly think I would be the only one thriled to try it just for fun. It would probably provide a great deal of goodwill for you guys, as well as further the industry's understanding of what constitutes a good take-home problem.