1     public boolean search(int [] A,int target){
 2        if(A==null||A.length==0)
 3          return false;
 4         
 5        int low = 0;
 6        int high = A.length-1;
 7       
 8        while(low <= high){
 9            int mid = (low + high)/2;
10            if(target < A[mid]){
11                if(A[mid]<A[high])//right side is sorted
12                  high = mid - 1;//target must in left side
13                else if(A[mid]==A[high])//cannot tell right is sorted, move pointer high
14                  high--;
15                else//left side is sorted
16                  if(target<A[low])
17                     low = mid + 1;
18                  else 
19                     high = mid - 1;
20            }else if(target > A[mid]){
21                if(A[low]<A[mid])//left side is sorted
22                  low = mid + 1;//target must in right side
23                else if(A[low]==A[mid])//cannot tell left is sorted, move pointer low
24                  low++;
25                else//right side is sorted
26                  if(target>A[high])
27                     high = mid - 1;
28                  else
29                     low = mid + 1;
30            }else
31              return true;
32        }
33        
34        return false;
35 }