Merge Sorted Array II

Merge two given sorted integer array A and B into a new sorted integer array.

Example
A=[1,2,3,4]

B=[2,4,5,6]

return [1,2,2,3,4,4,5,6]

class Solution {
    /**
     * @param A and B: sorted integer array A and B.
     * @return: A new sorted integer array
     */
    public ArrayList<Integer> mergeSortedArray(ArrayList<Integer> A, ArrayList<Integer> B) {
        // write your code here
        if(A==null||A.isEmpty())return B;
        if(B==null||B.isEmpty())return A;
        ArrayList<Integer> C=new ArrayList<Integer>();
        int alen=A.size(),blen=B.size();
        int i=0,j=0;
        while(i<alen&&j<blen){
          if(A.get(i)<B.get(j)){
            C.add(A.get(i));
            i++;
          }else{
            C.add(B.get(j));
            j++;
          }
        }
          while(i<alen){
            C.add(A.get(i));
            i++;
          }
          while(j<blen){
            C.add(B.get(j));
            j++;
          }

        return C;
    }
}