Search in rotated sorted array -- Leetcode

Question:

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.

Answer:

1. public int search(int[] A, int target) {  
2.     if(A==null || A.length==0)  
3.         return -1;  
4.     int l = 0;  
5.     int r = A.length-1;  
6.     while(l<=r)  
7.     {  
8.         int m = (l+r)/2;  
9.         if(target == A[m])  
10.             return m;  
11.         if(A[m]<A[r])  
12.         {  
13.             if(target>A[m] && target<=A[r])  
14.                 l = m+1;  
15.             else  
16.                 r = m-1;  
17.         }  
18.         else  
19.         {  
20.             if(target>=A[l] && target<A[m])  
21.                 r = m-1;  
22.             else  
23.                 l = m+1;                      
24.         }  
25.     }  
26.     return -1;  
27. }