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?

Analysis

作为Find Minimum in Rotated Sorted Array 的follow-up，差别在于是否有重复。跟Search in Rotated Sorted Array II 类似，处理nums[mid] == nums[right]的情况即可，移动搜索边界right--

Solution

Template #3

class Solution {
    public int findMin(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        }
        int left = 0, right = nums.length - 1;
        while (left + 1 < right) {
            int mid = left + (right - left) / 2;
            if (nums[mid] > nums[right]) {
                left = mid;
            } else if (nums[mid] < nums[right]) {
                right = mid;
            } else {
                right--;
            }
        }
        return Math.min(nums[left], nums[right]);
    }
}