Lintcode: Merge Sorted Array

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]



Challenge

How can you optimize your algorithm if one array is very large and the other is very small?

没什么好说的，Arraylist来做merge, 建一个新ArrayList

 1 class Solution {

 2     /**

 3      * @param A and B: sorted integer array A and B.

 4      * @return: A new sorted integer array

 5      */

 6     public ArrayList<Integer> mergeSortedArray(ArrayList<Integer> A, ArrayList<Integer> B) {

 7         // write your code here

 8         if (A==null || A.size()==0) return B;

 9         if (B==null || B.size()==0) return A;

10         ArrayList<Integer> res = new ArrayList<Integer>();

11         int i=0, j=0;

12         for (int k=0; k<A.size()+B.size(); k++) {

13             if (i<A.size() && j<B.size() && A.get(i) < B.get(j)) {

14                 res.add(A.get(i));

15                 i++;

16             }

17             else if (i<A.size() && j<B.size() && A.get(i) >= B.get(j)){

18                 res.add(B.get(j));

19                 j++;

20             }

21             else if (i<A.size()) {

22                 res.add(A.get(i));

23                 i++;

24             }

25             else {

26                 res.add(B.get(j));

27                 j++;

28             }

29         }

30         return res;

31     }

32 }