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 will tell you whether the number I picked is higher or lower than your guess.

You call a pre-defined API int guess(int num), which returns 3 possible results:

• 1: The number I picked is lower than your guess (i.e. pick < num).
• 1: The number I picked is higher than your guess (i.e. pick > num).
• 0: The number I picked is equal to your guess (i.e. pick == num).

Return the number that I picked.

Example 1:

Input: n = 10, pick = 6 Output: 6 

Example 2:

Input: n = 1, pick = 1 Output: 1 

Example 3:

Input: n = 2, pick = 1 Output: 1 

Example 4:

Input: n = 2, pick = 2 Output: 2 

Constraints:

• 1 <= n <= 231 - 1
• 1 <= pick <= n

猜数字游戏的规则如下：

• 每轮游戏，我都会从 1 到 n 随机选择一个数字。 请你猜选出的是哪个数字。
• 如果你猜错了，我会告诉你，你猜测的数字比我选出的数字是大了还是小了。

你可以通过调用一个预先定义好的接口 int guess(int num) 来获取猜测结果，返回值一共有 3 种可能的情况（-1，1 或 0）：

• 1：我选出的数字比你猜的数字小 pick < num
• 1：我选出的数字比你猜的数字大 pick > num
• 0：我选出的数字和你猜的数字一样。恭喜！你猜对了！pick == num

返回我选出的数字。

• 这一题是简单题，和小时候玩的猜大猜小的游戏一样。思路很简单，二分查找即可。这一题和第 278 题类似。

package leetcode import"sort"/** * 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 * func guess(num int) int; */funcguessNumber(nint) int { returnsort.Search(n, func(xint) bool { returnguess(x) <=0 }) } funcguess(numint) int { return0 }