Binary search requires splitting the search space into two halves, then asking “is it in that half?”

Normally the “is it in that half?” check involves a numerical comparison: test value versus target value. “higher or lower” here gets you to “is it in that half?”

So finding the midpoint seems like a core part of the process, but really that’s just a shortcut in the case of comparable values, that helps you split into two and check membership.

I admit I couldn’t think of that either: just alter half the items and check for effect.