Find Minimum in Rotated Sorted Array II

LeetCode #154

Description:

Follow up for "Find Minimum in Rotated Sorted Array": What if duplicates are allowed?

Would this affect the run-time complexity? How and why? 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:

Note

Idea:

这个与Search in Rotated Sorted ArrayII非常像，但是需要用[start, end] but not [start, end). 但update的方式几乎一样。

Time: O(n).

Code:

class Solution {
public:
    int findMin(vector<int>& nums) {
        int start=0;
        int end=nums.size()-1;

        while(start<end){
            if(nums[start]<nums[end]) return nums[start];

            int mid = start +(end-start)/2;
            if(nums[start] < nums[mid]) start = mid+1;
            else if(nums[start] > nums[mid]) end = mid;
            else start++;
        }

        return nums[start];

    }
};