LeetCode162—Find Peak Element

最新推荐文章于 2023-12-25 00:15:00 发布

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本文介绍了一种寻找峰值元素的方法。峰值元素是指比其邻居大的元素。文章提供了一个C++实现的例子，该方法适用于输入数组中不存在相等相邻元素的情况，并考虑了数组两端为负无穷的特殊情况。

原题

原题链接

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

Given an input array where num[i] ≠ num[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 num[-1] = num[n] = -∞.

For example, in array [1, 2, 3, 1], 3 is a peak element and your function should return the index number 2.

分析

比较简单，考虑题目有个条件叫做数组的两个边界都是负无穷，就得考虑[1,2,3]或者[3,2,1]这样的输入

class Solution {
public:
    int findPeakElement(vector<int>& nums) {
        for(int i=0;i<nums.size();i++)
        {
            if(i==0&&nums[i]>nums[i+1])
            {
                return i;
            }
            else if(i==nums.size()-1&&nums[i]>nums[i-1])
            {
                return i;
            }
            else
            {
                if(nums[i]>nums[i-1]&&nums[i]>nums[i+1])
                    return i;
            }
        }
        return 0;
    }
};