# 算法原地址
https://leetcode-cn.com/problems/add-two-numbers/comments/
# 思路
对位相加，考虑一下进位就可以
# 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 addTwoNumbers(ListNode l1, ListNode l2) {
ListNode root = new ListNode(0);
ListNode currentHead = root;
int carry = 0;
while(l1 != null || l2 != null || carry != 0) {
int l1Val = l1 != null ? l1.val : 0;
int l2Val = l2 != null ? l2.val : 0;
int sumVal = l1Val + l2Val + carry;
carry = sumVal / 10;
sumVal = sumVal%10;
ListNode nextNode = new ListNode(sumVal);
currentHead.next = nextNode;
currentHead = nextNode;
if(l1 != null) l1 = l1.next;
if(l2 != null) l2 = l2.next;
}
return root.next;
}
}
```
2.两数相加（链表）
