[leetcode]162. Find Peak Element

class Solution {public:    int findPeakElement(vector<int>& nums) {                int l=0;        int r=nums.size()-1;                return find(nums,l,r);    }    int find(vector<int>& nums,int l,int r)    {        if(l==r)        return l;        int mid=(l+r)/2;        if(nums[mid]>nums[mid+1])            return find(nums,l,mid);        else             return find(nums,mid+1,r);    }};