"""
162. Find Peak Element
Difficulty: Medium
https://leetcode.com/problems/find-peak-element/

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A peak element is an element that is strictly greater than its
neighbors.

Given a 0-indexed 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] = -∞. In other words,
an element is always considered to be strictly greater than a neighbor
that is outside the array.

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

        • -2^31 <= nums[i] <= 2^31 - 1

        • nums[i] != nums[i + 1] for all valid i.
"""


class Solution:
    def findPeakElement(self, nums: list[int]) -> int:
        left, right = 0, len(nums) - 1
        while left < right:
            mid = (left + right) // 2
            if nums[mid] < nums[mid + 1]:
                left = mid + 1
            else:
                right = mid

        return left