Solution21.java

/**
 * Created by slade on 2019/6/4.
 */


public class Solution21 {
 public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
 ListNode ln1 = new ListNode(0);
 ListNode ln2 = ln1;

 while (l1 !=null && l2!=null){
 if (l1.val<=l2.val){
 ln2.next = l1;
 l1 = l1.next;
 }else {
 ln2.next = l2;
 l2 = l2.next;
 }
 ln2 = ln2.next;
 }
 if (l1==null){
 ln2.next=l2;
 }
 if (l2==null){
 ln2.next=l1;
 }
 return ln1.next;
 }
 }


class ListNode {
 int val;
 ListNode next;

 ListNode(int x) {
 val = x;
 }
}