162. Find Peak Element

最新推荐文章于 2022-08-20 10:00:00 发布

SnailRunFast

最新推荐文章于 2022-08-20 10:00:00 发布

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本文介绍了一种在给定数组中寻找峰值元素的算法，峰值元素定义为大于其邻居的元素。文章提供了一个示例代码，使用迭代方法遍历数组，找到峰值元素并返回其索引。该解决方案满足了对数复杂度的要求。

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162. Find Peak Element

Medium

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

Given an input array nums, where nums[i] ≠ nums[i+1], find a peak element and return its index.

The array may contain multiple peaks, in that case return the index to any one of the peaks is fine.

You may imagine that nums[-1] = nums[n] = -∞.

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: 1 or 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.

Note:

Your solution should be in logarithmic complexity.

class Solution {
    public int findPeakElement(int[] nums) {
        int maxPeakVal = nums[0], maxPeakIdx = 0;
        for (int i = 1; i < nums.length; i++) {      
            if (nums[i] > nums[i - 1]) {
                if (nums[i] > maxPeakVal) {
                    maxPeakVal = nums[i];
                    maxPeakIdx = i;
                }
            }
        }
        
        return maxPeakIdx;
    }
}