```
int findPeakElement(vector<int>& nums) {
int l = 0, r = nums.size() - 1;
while(l < r) {
int mid = (l + r) / 2;
if(mid == 0 || nums[mid] > nums[mid - 1]) {
if(nums[mid] < nums[mid + 1]) l = mid + 1;
else r = mid;
}
else r = mid - 1;
}
return l;
}
```