【LeetCode445】 Add Two Numbers II★★

 1 import java.util.Stack;
 2 //public class LeetCode445为测试代码
 3 public class LeetCode445 {
 4     public static void main(String[] args) {
 5         ListNode l1=new ListNode(7),l11=new ListNode(2),l12=new ListNode(4),l13=new ListNode(3);
 6         l1.next=l11;
 7         l11.next=l12;
 8         l12.next=l13;
 9         System.out.print("Input:["+l1.val+","+l11.val+","+l12.val+","+l13.val+"]");
10         ListNode l2=new ListNode(5),l21=new ListNode(6),l22=new ListNode(4);
11         l2.next=l21;
12         l21.next=l22;
13         System.out.println(",["+l2.val+","+l21.val+","+l22.val+"]");
14         ListNode list=new Solution().addTwoNumbers(l1, l2);
15         if(list!=null)
16             System.out.print("output：["+list.val);
17         while(list.next!=null){
18             System.out.print(","+list.next.val);
19             list.next=list.next.next;
20         }
21         System.out.println("]");
22     }
23 }
24 class Solution {
25 public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
26         Stack<Integer> stack1=new Stack<Integer>();
27         Stack<Integer> stack2=new Stack<Integer>();
28         while(l1!=null){
29             stack1.push(l1.val);
30             l1=l1.next;
31         }
32         while(l2!=null){
33             stack2.push(l2.val);
34             l2=l2.next;
35         }
36         int carry=0;
37         ListNode resultList=new ListNode(0);
38         while(!stack1.empty()||!stack2.empty()){
39             int sum=carry;
40             if(!stack1.empty()) sum+=stack1.pop();
41             if(!stack2.empty()) sum+=stack2.pop();
42             resultList.val=sum%10;
43             ListNode newHead=new ListNode(sum/10);
44             newHead.next=resultList;
45             resultList=newHead;
46             carry=sum/10;
47         }
48         return resultList.val==0?resultList.next:resultList;
49     }
50 }
51 class ListNode {
52        int val;
53        ListNode next;
54        ListNode(int x) { val = x; }
55       }