Solution (leetcode-in-java 1.23 API)

java.lang.Object
- g0801_0900.s0852_peak_index_in_a_mountain_array.Solution

```
public class Solution
extends Object
```
852 - Peak Index in a Mountain Array.
Easy

Let’s call an array arr a mountain if the following properties hold:
- 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]
Given an integer array arr that is guaranteed to be a mountain, return any i such that arr[0] < arr[1] < ... arr[i - 1] < arr[i] > arr[i + 1] > ... > arr[arr.length - 1].

Example 1:

Input: arr = [0,1,0]

Output: 1

Example 2:

Input: arr = [0,2,1,0]

Output: 1

Example 3:

Input: arr = [0,10,5,2]

Output: 1

Constraints:
- 3 <= arr.length <= 10⁴
- 0 <= arr[i] <= 10⁶
- arr is guaranteed to be a mountain array.
Follow up: Finding the O(n) is straightforward, could you find an O(log(n)) solution?

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  int peakIndexInMountainArray(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

peakIndexInMountainArray

public int peakIndexInMountainArray(int[] arr)