374.guess-number-higher-or-lower.java

/*
 * @lc app=leetcode id=374 lang=java
 *
 * [374] Guess Number Higher or Lower
 */

// @lc code=start
/** 
 * Forward declaration of guess API.
 * @param  num   your guess
 * @return 	     -1 if num is lower than the guess number
 *			      1 if num is higher than the guess number
 *               otherwise return 0
 * int guess(int num);
 */

public class Solution extends GuessGame {
    public int guessNumber(int n) {
        int low = 0;
        int high = n;

        while (low <= high) {
            int mid = low + (high - low) / 2;

            if (guess(mid) == 0) {
                return mid;
            } else if (guess(mid) == -1) {
                high = mid - 1;
            } else {
                low = mid + 1;
            }
        }
        return 0;
    }
}
// @lc code=end