# Difference between revisions of "TADM2E 4.32"

(1) Do a binary search within the range of $1-n$. You guess the right number within O(log n) questions.
(2) If you don't know n start with a random number $2^i$ and if it is larger than the number you are looking for do a binary search within $1-2^i$ as in (1). If $2^i$ is less then guess $2^{i+1}$ and repeat.