```
def search(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: int
"""
if not nums:
return -1
start = 0
end = len(nums) - 1
while start <= end:
mid = (end + start) // 2
if nums[mid] == target:
return mid
if nums[start] <= nums[mid]: # left is sorted
if nums[start] <= target <= nums[mid]:
end = mid - 1
else:
start = mid + 1
else:
if nums[mid] < nums[end]: # right part is sorted
if nums[mid] <= target <= nums[end]:
start = mid + 1
else:
end = mid - 1
return -1
```