Guess Number Higher or Lower

Description

We are playing the Guess Game. The game is as follows:

I pick a number from 1 to n. You have to guess which number I picked (the number I picked stays the same throughout the game).

Every time you guess wrong, I will tell you whether the number I picked is higher or lower than your guess.

You call a pre-defined API int guess(int num), which returns three possible results:

- -1: Your guess is higher than the number I picked (i.e. num > pick).

- 1: Your guess is lower than the number I picked (i.e. num < pick).

- 0: your guess is equal to the number I picked (i.e. num == pick).

Return the number that I picked.