```
class Solution {
public:
int search(vector<int>& nums, int target) {
int l = 0, r = nums.size()-1;
while (l <= r) {
int mid = (l+r) / 2;
if (target == nums[mid])
return mid;
// there exists rotation; the middle element is in the left part of the array
if (nums[mid] > nums[r]) {
if (target < nums[mid] && target >= nums[l])
r = mid - 1;
else
l = mid + 1;
}
// there exists rotation; the middle element is in the right part of the array
else if (nums[mid] < nums[l]) {
if (target > nums[mid] && target <= nums[r])
l = mid + 1;
else
r = mid - 1;
}
// there is no rotation; just like normal binary search
else {
if (target < nums[mid])
r = mid - 1;
else
l = mid + 1;
}
}
return -1;
}
};
```