---
title: '162. Find Peak Element'
description: A peak element is an element that is strictly greater than its neighbors
icon: dot
topics:
  - { name: "Array", slug: "array" }
  - { name: "Binary Search", slug: "binary-search" }
issue: "https://github.com/prdlk/leetcode/issues/64"
sidebar:
  label: 'Find Peak Element'
  badge: 'Medium'
---

::::warning
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.`

## Solution

```py
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
```