LeetCode162—Find Peak Element

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
= -∞.

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;
}
};