leetcode81---Search in Rotated Sorted Array II

问题描述:

Follow up for “Search in Rotated Sorted Array”:
What if duplicates are allowed?

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

Write a function to determine if a given target is in the array.

特点:含有重复数字。如[1,3,1,1,1] 3这种情况。

问题求解:

class Solution {
public:
    bool search(vector<int>& nums, int target) {
        int n=nums.size();
        if(n==0) return false;
        int low=0, high=n-1, mid;
        while(low<=high)
        {
            mid=(low+high)/2;
            if(nums[mid]==target) return true;
            else if(nums[low] < nums[mid])
            {
                if(target<nums[mid] && target>=nums[low])
                {
                    high=mid-1;
                }
                else
                {
                    low=mid+1;
                }
            }
            else if(nums[low] > nums[mid])
            {
                if(target<=nums[high] && target>nums[mid])
                {
                    low=mid+1;
                }
                else
                {
                    high=mid-1;
                }
            }
            else//如[1,3,1,1,1] 3这种情况
            {//nums[low] == nums[mid]
                low++;
            }
        }
        return false;
    }
};

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