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Abhishek Chaudhary
Abhishek Chaudhary

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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.

SOLUTION:

class Solution:
    def findPeakElement(self, nums: List[int]) -> int:
        n = len(nums)
        for i in range(n):
            left = nums[i] > nums[i - 1] if i > 0 else True
            right = nums[i] > nums[i + 1] if i < n - 1 else True
            if left and right:
                return i
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