leetcode.com/python/153_Find_Minimum_in_Rotated_Sorted_Array.py

class Solution(object):
    def findMin(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        n = len(nums)
        if n == 0:
            return -1
        if n == 1:
            return nums[0]
        rotatingIdx = self.findRotatingIndex(nums, 0, n - 1)
        return nums[rotatingIdx]

    def findRotatingIndex(self, nums, left, right):
        if nums[left] < nums[right]:  # nums is not rotated, it's already sorted
            return 0
        while left <= right:
            mid = (left + right) // 2
            if nums[mid] > nums[mid + 1]:  # we have found our rotating index
                return mid + 1
            elif (nums[mid] < nums[mid + 1]) and (nums[mid] < nums[mid - 1]):  # we have found our rotating index
                return mid
            else:
                if nums[mid] > nums[left]:
                    left = mid + 1
                else:
                    right = mid - 1