g0801_0900.s0845_longest_mountain_in_array.readme.md Maven / Gradle / Ivy
845\. Longest Mountain in Array
Medium
You may recall that an array `arr` is a **mountain array** if and only if:
*   `arr.length >= 3`
*   There exists some index `i` (**0-indexed**) with `0 < i < arr.length - 1` such that:
    *   `arr[0] < arr[1] < ... < arr[i - 1] < arr[i]`
    *   `arr[i] > arr[i + 1] > ... > arr[arr.length - 1]`
Given an integer array `arr`, return _the length of the longest subarray, which is a mountain_. Return `0` if there is no mountain subarray.
**Example 1:**
**Input:** arr = [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:**
**Input:** arr = [2,2,2]
**Output:** 0
**Explanation:** There is no mountain.
**Constraints:**
*   1 <= arr.length <= 104
*   0 <= arr[i] <= 104
**Follow up:**
*   Can you solve it using only one pass?
*   Can you solve it in `O(1)` space?    © 2015 - 2025 Weber Informatics LLC | Privacy Policy