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.

class Solution
{
public:
	int search(int A[],int n,int target)
	{
		if(target==A[n-1])
			return n-1;
		if(target==A[0])
			return 0;
		if(n==0)
			return -1;
		int first = 0;
		int end = n-1;
		int mid = 0;
		while(first<end)
		{
			mid = (first+end)/2;
			if(target==A[mid])
				return mid;
			else if( target>A[mid])
			{
				if(target>A[n-1] && A[mid]<A[first])
					end = mid;
				else
					first = mid+1;
			}
			else
			{
				if(A[mid]>A[n-1] && target<A[first])
					first = mid+1;
				else
					end = mid;
			}
		}
		return -1;
	}
};

Obviously,the algorithm is dichotomy(二分法).
 My first to the problem is to find the pivot,so I use the for loop to find out it,and when I submit it for the first time ,the excuted time is limited.And then I use one while loop,but the situation is a little complex. Step  by step,test for many times,I succeeded finally.

So,I learned that we could think from the problem we have known,and improve it.In addition,we must have patience,I failed for many times,and I lose temper in the middle,lace of enough patience.It is simple for someone who is good at programming.I know my programming skills is very low.However,I am trying and fighting!Coding more,reading more and thinking more!