374. Guess Number Higher or Lower

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.

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.

Example 1:

Input: n = 10, pick = 6 Output: 6

Example 2:

Input: n = 1, pick = 1 Output: 1

Example 3:

Input: n = 2, pick = 1 Output: 1

Constraints:

1 <= n <= 231 - 1 1 <= pick <= n