Is it possible that a person will finds the number what his friend thinks in my mind. the number should between 1-100 via java code

Question

the person will think a number between 1-100. The Questionnaire can ask n number of condition, i.e the number is even or odd, the number is perfect square or prime number, sum of squares etc.

score 3 · Answer 1 · edited Mar 20 '12 at 12:53

3

It is certainly possible to find a number between 1 and 100 by asking 100 questions, namely:

It is possible to do it with 7 questions by binary search. Writing the number in base 2, ask:

I don't know anything about Java code, but that's for a different website, anyway.

edited Mar 20 '12 at 12:53

Ilmari Karonen

answered Mar 20 '12 at 11:31

Gerry Myerson

2

Indeed, even 7 questions of the form "Is the number greater than $x$?" will do. (Hint: start with $x=50$.) The binary expansion technique does, however, have the advantage that you can decide all the questions you will ask in advance. – Ilmari Karonen Mar 20 '12 at 12:51

1 Answers1