合并2个有序链表
/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; this.next = next; } * } */ class Solution { public ListNode mergeTwoLists(ListNode list1, ListNode list2) { if(list1 == null) return list2; if(list2 ==null) return list1; ListNode head = new ListNode(); ListNode cur = head; while(list1!=null && list2!=null){ if(list1.val < list2.val){ cur.next = list1; list1 = list1.next; }else{ cur.next = list2; list2 = list2.next; } cur = cur.next; } if(list1==null) cur.next = list2; if(list2==null) cur.next = list1; return head.next; } }