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