[photochemsyn]

Wouldn't one normally just try to convert this to an unambiguous discrete problem, something like:

Given:

(1) the ordered sequence of whole numbers (1, 2, ... , 99, 100) and

(2) an unknown value N that is a member of this sequence,

(3) the following tests (a candidate is a guess at the value of N), and two separate threads to run tests:

(A) if candidate <= N : true & thread continues (another candidate can be checked with that thread)

(B) candidate > N : false & thread terminates (no more candidates can be checked with that thread)

Determine the best strategy for finding N (minimize the number of tests while leaving at least one thread alive)

Determine the worst case for the number of tests needed to find N using this optimal strategy.