问题描述:
java代码:
java
/**
* 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) {
ListNode res = new ListNode(0);
ListNode cur = res;
while(list1 != null || list2 != null){
if(list1 != null && list2 != null){
if (list1.val == list2.val){
cur.next = new ListNode(list1.val);
cur = cur.next;
cur.next = new ListNode(list2.val);
list1 = list1.next;
list2 = list2.next;
}else{
if(list1.val>list2.val){
cur.next = new ListNode(list2.val);
list2 = list2.next;
}else{
cur.next = new ListNode(list1.val);
list1 = list1.next;
}
}
}else if(list1 != null){
cur.next = new ListNode(list1.val);
list1 = list1.next;
}else if(list2 != null){
cur.next = new ListNode(list2.val);
list2 = list2.next;
}
cur = cur.next;
}
return res.next;
}
}