147. 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:

n = 10, I pick 6.Return 6.

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/* 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 {    /*二分查找*/    public int guessNumber(int n) {                if(n<=0){            return 1;        }                return binaryGuess(0,n);    }    /*每次都是猜最大值和最小值之间的*/    private int binaryGuess(int low, int high){        int mid = low + (high-low)/2;        int temp = guess(mid);                if(temp == 0){            return mid;        }else{            if(temp == 1){                low = mid +1;            }else{                high = mid -1;            }            return binaryGuess(low,high);        }    }}