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.
Input: nums = [1,2,3,1] Output: 2 Explanation: 3 is a peak element and your function should return the index number 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.
1 <= nums.length <= 1000
-231 <= nums[i] <= 231 - 1
nums[i] != nums[i + 1]for all valid