Interview Question

## Problem : 

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




##Solution: 


int guessNumber(int n) {
    int left = 1;
    int right = n;
    while (left <= right) {
        int mid = left + (right - left) / 2;
        int result = guess(mid);
        if (result == 0) {
            return mid;
        } else if (result == -1) {
            right = mid - 1;
        } else {
            left = mid + 1;
        }
    }
    
    return -1; // number not found
}