题目链接

21.合并两个有序链表

class Solution {public ListNode mergeTwoLists(ListNode list1, ListNode list2) {ListNode p1 = list1;ListNode p2 = list2;ListNode p = new ListNode(0);ListNode cur = p;while (p1 != null && p2 != null) {if (p1.val > p2.val) {list2 = list2.next;cur.next = p2;cur = p2;p2 = list2;} else {list1 = list1.next;cur.next = p1;cur = p1;p1 = list1;}}if (p1 != null) {cur.next = p1;}if (p2 != null) {cur.next = p2;}return p.next;}
}

小结：注意题目中的链表没有头结点，边界问题。