g0801_0900.s0845_longest_mountain_in_array

Class Solution

java.lang.Object

g0801_0900.s0845_longest_mountain_in_array.Solution

public class Solution
extends Object

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?

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	longestMountain(int[] arr)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

longestMountain

public int longestMountain(int[] arr)