0374. Guess Number Higher or Lower

# 374. Guess Number Higher or Lower#

## 题目 #

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`

## 题目大意 #

• 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。

• 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

## 解题思路 #

• 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。

## 代码 #

``````package leetcode

import "sort"

/**
* Forward declaration of guess API.
* @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;
*/

func guessNumber(n int) int {
return sort.Search(n, func(x int) bool { return guess(x) <= 0 })
}

func guess(num int) int {
return 0
}
`````` Jun 22, 2022 Edit this page