21. Merge Two Sorted Lists

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.

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public ListNode mergeTwoLists(ListNode l1, ListNode l2) { ListNode head = new ListNode(0); ListNode p = head; while(l1!=null||l2!=null){ if(l1!=null&&l2!=null){ if(l1.val < l2.val){ p.next = l1; l1=l1.next; }else{ p.next=l2; l2=l2.next; } p = p.next; }else if(l1==null){ p.next = l2; break; }else if(l2==null){ p.next = l1; break; } } return head.next; }