[leetcode 162] Find Peak Element

最新推荐文章于 2021-03-16 14:43:49 发布

原创最新推荐文章于 2021-03-16 14:43:49 发布 · 346 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#leetcode #Array

[LeetCode 刷题] 专栏收录该内容

158 篇文章

订阅专栏

本文介绍了一种在给定数组中查找峰元素的方法，并提供了一个简单的C++类实现。峰元素定义为大于其相邻元素的元素。算法遍历数组，找到第一个下降的元素即为峰元素。

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.

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