https://leetcode.com/problems/merge-two-sorted-lists/description/
输入: 两个排好序的链表
输出: 两个链表连接起来,并且是排好序的
思路:
循环遍历两个链表,判断当前节点的大小,需要注意长度不等
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
if(l1==null){
return l2;
}
if(l2==null){
return l1;
}
ListNode res = new ListNode(-1);
ListNode i=l1,j=l2,item=res;
do{
if(i!=null&&j!=null){
if(i.val<j.val){
item.next=i;
i=i.next;
item=item.next;
}else{
item.next=j;
j=j.next;
item=item.next;
}
}else if(j==null){
item.next=i;
i=i.next;
item=item.next;
}else if(i==null){
item.next=j;
j=j.next;
item=item.next;
}
}while(i!=null||j!=null);
return res.next;
}
}
