Find Minimum in Rotated Sorted Array II

Desicription

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:

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Input: [1,3,5]
Output: 1

Example 2:

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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?

Solution

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class Solution {
public:
    int findMin(vector<int>& nums) {
        int left = 0;
        int right = nums.size() - 1;
        while(left < right) {
            int mid = (left + right) >> 1;
            if(nums[mid] > nums[right])
                left = mid + 1;
            else if(nums[mid] < nums[right])
                right = mid;
            else {
                if(nums[left] == nums[mid])
                    left++, right--;
                else
                    right = mid;
            }
        }
        return nums[right];
    }
};