Find Peak Element leetCode

 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.


class Solution {
    public int findPeakElement(int[] nums) {
        int left = 0;
        int right = nums.length - 1;

        while (left < right) {
            int mid = left + (right - left) / 2;

            // Compare mid and mid+1 to decide the direction
            if (nums[mid] > nums[mid + 1]) {
                // Peak is in the left half (including mid)
                right = mid;
            } else {
                // Peak is in the right half (excluding mid)
                left = mid + 1;
            }
        }

        // left == right is the peak index
        return left;
    }
}

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