LeetCode 374 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.

还是二分查找啦。若是查找某个数，猜某个数，大多情况下都是二分查找。

	/* The guess API is defined in the parent class GuessGame.
   @param n, 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, high = n, result;
			while (true) {
				result = low + (high - low) / 2;
				if (guess(result) == 0) return result;
				else if (guess(result) == 1) {
					low = result + 1;
				} else high = result - 1;
			}
		}
	}