Had the first round at OCI for Software Engineer entry level (1-3 years exp). Unluckily got a tough one, still can't figure out the solution. Any idea how to solve this?

Question -

Given an int array for a range of numbers, return a list of numbers that when turned upside down would have a significant number but a different value. eg. 66 turned upside down would be 99, but not 69, as 69 turned upside down will still be 69 and similarly 88 as well.

Closest problem on leetcode is Strobogrammatic number 3 but still not quite similar