154. Find Minimum in Rotated Sorted Array II

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.

(i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]).

Find the minimum element.

The array may contain duplicates.

Example 1:

Input: [1,3,5]

Output: 1

Example 2:

Input: [2,2,2,0,1]

Output: 0

Note:

• This is a follow up problem to Find Minimum in Rotated Sorted Array.

• Would allow duplicates affect the run-time complexity? How and why? -This affects the worst case complexity to be O(n) since the each iteration the input size at worst only shrink one step (nums[mid] == nums[right])

Thoughts:

1. Handle duplicates: if (nums[mid] == nums[right], then nums[mid] maintains the value and right can only reduce one.

Code

class Solution(object):
    def findMin(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        left, right = 0, len(nums) - 1
        while left < right:
            mid = (right - left >> 1) + left
            if  nums[mid] < nums[right]:
                right = mid

            elif nums[mid] > nums[right]:
                left = mid + 1

            else:
                right -= 1


        return nums[left] # left = right