mirror of
https://github.com/halfrost/LeetCode-Go.git
synced 2025-07-05 16:36:41 +08:00
55 lines
1.2 KiB
Markdown
55 lines
1.2 KiB
Markdown
# [845. Longest Mountain in Array](https://leetcode.com/problems/longest-mountain-in-array/)
|
|
|
|
## 题目
|
|
|
|
Let's call any (contiguous) subarray B (of A) a mountain if the following properties hold:
|
|
|
|
- B.length >= 3
|
|
- There exists some 0 < i < B.length - 1 such that B[0] < B[1] < ... B[i-1] < B[i] > B[i+1] > ... > B[B.length - 1]
|
|
(Note that B could be any subarray of A, including the entire array A.)
|
|
|
|
Given an array A of integers, return the length of the longest mountain.
|
|
|
|
Return 0 if there is no mountain.
|
|
|
|
|
|
|
|
|
|
Example 1:
|
|
|
|
```c
|
|
Input: [2,1,4,7,3,2,5]
|
|
Output: 5
|
|
Explanation: The largest mountain is [1,4,7,3,2] which has length 5.
|
|
```
|
|
|
|
Example 2:
|
|
|
|
```c
|
|
Input: [2,2,2]
|
|
Output: 0
|
|
Explanation: There is no mountain.
|
|
```
|
|
|
|
Note:
|
|
|
|
- 0 <= A.length <= 10000
|
|
- 0 <= A[i] <= 10000
|
|
|
|
|
|
Follow up:
|
|
|
|
- Can you solve it using only one pass?
|
|
- Can you solve it in O(1) space?
|
|
|
|
## 题目大意
|
|
|
|
这道题考察的是滑动窗口的问题。
|
|
|
|
给出一个数组，要求求出这个数组里面“山”最长的长度。“山”的意思是，从一个数开始逐渐上升，到顶以后，逐渐下降。
|
|
|
|
## 解题思路
|
|
|
|
这道题解题思路也是滑动窗口，只不过在滑动的过程中多判断一个上升和下降的状态即可。
|
|
|