Guess_Number_Higher_or_Lower.java

//Leetcode 374. Guess Number Higher or Lower
//Question - https://leetcode.com/problems/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'll tell you whether the number is higher or lower.

You call a pre-defined API guess(int num) which returns 3 possible results (-1, 1, or 0):

-1 : My number is lower
 1 : My number is higher
 0 : Congrats! You got it!

Example :

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

*/

/* The guess API is defined in the parent class GuessGame.
   @param num, your guess
   @return -1 if my number is lower, 1 if my number is higher, otherwise return 0
      int guess(int num); */

public class Solution extends GuessGame {
    public int guessNumber(int n) {
        int low = 1;
        int high = n;
        
        while(low<=high){
            
            int mid = low + (high-low)/2;
            int res = guess(mid);

            if(res==0) return mid;
            else if(res==-1) high = mid - 1;
            else low = mid + 1;
        }
        return -1;
    }
}