Merge two sorted linked lists and return it as a new sorted list. The new list should be made by splicing together the nodes of the first two lists.
Example:
Input: 1->2->4, 1->3->4
Output: 1->1->2->3->4->4
Thoughts
- 使用一个dummyhead,串接新的list
- 比较
l1和l2，val小的加在list上 l1和l2全部遍历完即可得到merge的新list
Code(JAVA)
public ListNode mergeTwoLists(ListNode l1, ListNodel2) {
ListNode dummyHead = new ListNode(0);
ListNode cur = dummyHead;
while(l1 != null || l2 != null) {
if(l1 == null) {
cur.next = l2;
break;
}
if(l2 == null) {
cur.next = l1;
break;
}
if(l1.val < l2.val) {
cur.next = l1;
l1 = l1.next;
}
else {
cur.next = l2;
l2 = l2.next;
}
cur = cur.next;
}
return dummyHead.next;
}
