package MergeTwoSortedLists;

import commons.datastructures.ListNode;

/**

* User: Danyang

* Date: 1/20/2015

* Time: 10:40

*

* Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

*/

public class Solution {

/**

* Notice:

* 1. importance of using pre

* @param l1

* @param l2

* @return

*/

public ListNode mergeTwoLists(ListNode l1, ListNode l2) {

ListNode c1 = l1;

ListNode c2 = l2;

ListNode dummy = new ListNode(0);

ListNode pre = dummy;

while(c1!=null && c2!=null) {

pre.next = new ListNode(0);

ListNode c = pre.next;

if(c1.val<c2.val) {

c.val = c1.val;

c1 = c1.next;

}

else {

c.val = c2.val;

c2 = c2.next;

}

pre = pre.next;

}

if(c1==null)

pre.next = c2;

else

pre.next = c1;

return dummy.next;

}

public static void main(String[] args) {

ListNode ret = new Solution().mergeTwoLists(null, null);

}

}