Peak Element Finder

ArrayBinary Search

Given an array of integers, find a peak element and return its index. A peak element is one which is greater than its neighbors. For array boundaries, only one neighbor exists.

Note: If there are multiple peak elements, you may return the index of any of them.

Example 1

Input

[
  1,
  3,
  20,
  4,
  1,
  0
]

Output

Explanation. The element at index 2 is 20, which is greater than its neighbors 3 and 4.

Example 2

Input

Output

Explanation. The peak element 20 is at index 1, greater than its neighbor 10.

Example 3

Input

[
  2,
  2,
  2,
  2,
  3,
  2
]

Output

Explanation. The peak element 3 is at index 4, surrounded by 2s.

Follow-up: Can you implement your solution in a way that it works in logarithmic time complexity?

Constraints:

- The array will contain at least one element and may contain up to 1000 elements. - All elements will be integers.

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