Search in Rotated Sorted Array

Suppose a sorted array 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).

You are given a target value to search. If found in the array return its index, otherwise return -1.

You may assume no duplicate exists in the array.

 

C++代码实现：

#include<iostream>

using namespace std;



class Solution

{

public:

    int search(int A[], int n, int target)

    {

        int left=0;

        int right=n-1;

        int mid;

        while(left<=right)

        {

            mid=(left+right)/2;

            if(A[mid]==target)

                return mid;

            else if(A[mid]<target&&A[mid]>A[right])

                left=mid+1;

            else if(A[mid]<target&&A[mid]<A[right])

            {

                if(target>A[right])

                    right=mid-1;

                else if(target<A[right])

                    left=mid+1;

                else

                    return right;

            }

            else if(A[mid]>target&&A[mid]>A[right])

            {

                if(target>A[right])

                    right=mid-1;

                else if(target<A[right])

                    left=mid+1;

                else

                    return right;

            }

            else if(A[mid]>target&&A[mid]<A[right])

                right=mid-1;

            else

                return -1;

        }

        if(left>right)

            return -1;

        else

            return mid;

    }

};



int main()

{

    Solution s;

    int A[10]= {2,3,4,5,6,7,8,9,10,1};

    cout<<s.search(A,10,5)<<endl;

}