[LeetCode] 162. Find Peak Element

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.

寻找峰值。

峰值元素是指其值大于左右相邻值的元素。

给你一个输入数组 nums，找到峰值元素并返回其索引。数组可能包含多个峰值，在这种情况下，返回 任何一个峰值 所在位置即可。

你可以假设 nums[-1] = nums[n] = -∞ 。

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/find-peak-element
著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

给一个数组，数组满足条件nums[i] ≠ nums[i+1]，求数组峰值的下标。这个题的