Because we don't know the size. If we use len(nums), which would cause O(N), right?

Then there's no way we can solve this problem in O(lg n) in Python!?

Here's my AC code:

```
class Solution:
# @param {integer[]} nums
# @return {integer}
def findMin(self, nums):
beg = 0
end = len(nums)-1
while end>beg:
mid = (beg+end)/2
if nums[beg] <= nums[mid] and nums[mid] <= nums[end]:
return nums[beg]
if nums[mid] <= nums[beg] and nums[mid] <= nums[end]: # max, min, mid
end = mid
if nums[beg] <= nums[mid] and nums[mid] >= nums[end]: # mid, max, min
beg = mid+1
return nums[beg]
```