Longest Mountain in Array

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.

Follow up:

Example 1

      #
      #
      #     #
    # #     #
    # # #   #
#   # # # # #
# # # # # # #
2 1 4 7 3 2 5

Inputarr = [2,1,4,7,3,2,5]

Output5

The largest mountain is [1,4,7,3,2] which has length 5.

Example 2

# # #
# # #
2 2 2

Inputarr = [2,2,2]

Output0

There is no mountain.

Constraints