LeetCode——Find Minimum in Rotated Sorted Array II

Question

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.

Solution

抓住数组的特点。

Code

class Solution {
public:
    int findMin(vector<int>& nums) {
        int size = nums.size();
        if (size == 1)
            return nums[0];
        int low = 0;
        int high = size - 1;
        while (low < high) {
        	// 没用递归，所以注意求中间节点的方法
            int mid = low + (high - low) / 2;
            // 如果更小，那么会比右边的都小
            if (nums[mid] < nums[high])
                high = mid;
            // 如果更大，那最小的肯定在右边
            else if (nums[mid] > nums[high])
                low = mid + 1;
            // 如果相等，不知道最大值在左边还是在右边
            else
                high--;
        }
        return nums[low];
    }
};