package DecemberOf2013; class ListNode{     int val;     ListNode next;     public ListNode(int val) {         this.val = val;         this.next = null;     } } public class MergeTowSortedLists {     public ListNode mergeLists(ListNode l1, ListNode l2){         ListNode p1 = l1;         ListNode p2 = l2;         ListNode fadeHead = new ListNode(0);         ListNode pHead = fadeHead;         while(p1 != null && p2 != null){             if(p1.val <= p2.val){                 pHead.next = p1;                 p1 = p1.next;             }             else{                 pHead.next = p2;                 p2 = p2.next;             }             pHead = pHead.next;         }         if(p1 != null){             pHead.next = p1;         }         else{             pHead.next = p2;         }         return fadeHead.next;     } }