"Leetcode" Find Peak Element

A peak element is an element, which is greater than its neighbors.

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

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

May imagine 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.

Click to show spoilers.

Note:

Your solution should is in logarithmic complexity.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

1 classSolution {2  Public:3     intFindpeakelement (vector<int>&nums) {4         if(nums.size () = =0)returnNULL;5 6          for(intI=1; I<nums.size (); i++)7         {8             if(nums[0]>nums[1])9                 return 0;Ten             if(Nums[nums.size ()-1]>nums[nums.size ()-2]) One                 returnNums.size ()-1; A             if(nums[i]>nums[i-1]&&nums[i]>nums[i+1]) -                 returni; -  the         } -  -         returnNULL; -     } +};

"Leetcode" Find Peak Element