374. Guess Number Higher or Lower.java

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