程式語言 - LeetCode - C - 374. Guess Number Higher or Lower

參考資訊：
https://www.cnblogs.com/grandyang/p/5666502.html

題目：


解答：

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

int guess(int num);

int guessNumber(int n)
{
    int r = 0;
    int m = 0;
    int left = 0;
    int right = n;

    while (left < right) {
        m = left + ((right - left) >> 1);
        r = guess(m);

        if (r > 0) {
            left = m + 1;
        }
        else if (r < 0) {
            right = m;
        }
        else {
            return m;
        }
    }

    return left;
}