Find the Odd One Out Position

Every gift box on the shelf weighs the same — except one, which is hiding the surprise. 🎁

You get a list of weights where every value is identical except a single different one. Print the position (from 0) of the odd one out. There are at least 3 boxes.

Example:

Input: weights = [5, 5, 5, 9, 5] Output: 3

The first two boxes match, so 5 is the normal weight — the box that doesn't match it, 9, sits at position 3.