public class Solution
extends Object
162 - Find Peak Element\.
Medium
A peak element is an element that is strictly greater than its neighbors.
Given an integer array `nums`, find a peak element, and return its index. If the array contains multiple peaks, return the index to **any of the peaks**.
You may imagine that `nums[-1] = nums[n] = -∞`.
You must write an algorithm that runs in `O(log n)` time.
**Example 1:**
**Input:** nums = [1,2,3,1]
**Output:** 2
**Explanation:** 3 is a peak element and your function should return the index number 2.
**Example 2:**
**Input:** nums = [1,2,1,3,5,6,4]
**Output:** 5
**Explanation:** Your function can return either index number 1 where the peak element is 2, or index number 5 where the peak element is 6.
**Constraints:**
* `1 <= nums.length <= 1000`
* -231 <= nums[i] <= 231 - 1
* `nums[i] != nums[i + 1]` for all valid `i`.