Leetcode 81 Search in Rotated Sorted Array II

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

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

You are given a target value to search. If found in the array return true, otherwise return false.

Example 1:

Input: nums = [2,5,6,0,0,1,2], target = 0
Output: true
Example 2:

Input: nums = [2,5,6,0,0,1,2], target = 3
Output: false
Follow up:

This is a follow up problem to Search in Rotated Sorted Array, where nums may contain duplicates.
Would this affect the run-time complexity? How and why?

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/search-in-rotated-sorted-array-ii

class Solution {
public:
    bool search(vector<int>& nums, int target) {
        int first = 0;
        int last = nums.size();
        while(first != last)
        {
            int mid = first + (last - first) / 2;
            if(target == nums[mid])
            {
                return true;
            }
            if(nums[first] < nums[mid])
            {
                if(target >= nums[first] && target < nums[mid])
                {
                    last = mid;
                }
                else
                {
                    first = mid + 1;
                }
            }
            else if(nums[first] > nums[mid])
            {
                if(target > nums[mid] && target <= nums[last-1])
                {
                    first = mid + 1;
                }
                else
                {
                    last = mid;
                }

            }
            else
            {
                first++;
            }
        }
        return false;
    }
};