Given an array of integers `arr`

, return * true if and only if it is a valid mountain array*.

Recall that arr is a mountain array if and only if:

`arr.length >= 3`

- There exists some
`i`

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]`

**Example 1:**

Input:arr = [2,1]Output:false

**Example 2:**

Input:arr = [3,5,5]Output:false

**Example 3:**

Input:arr = [0,3,2,1]Output:true

**Constraints:**

`1 <= arr.length <= 10`

^{4}`0 <= arr[i] <= 10`

^{4}

class Solution {
public boolean validMountainArray(int[] arr) {
}
}