题目：
You are given two linked lists rePResenting two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
思路：
就像做加法一样，记得进位和判断结尾
packagelist;publicclassAddTwoNumbers {publicListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode p=newListNode(0);
ListNode node=p;intsum = 0;intcarry = 0;while(true) {if(l1 !=null&& l2 !=null) {
sum= l1.val + l2.val +carry;
l1=l1.next;
l2=l2.next;
}elseif(l1 !=null) {
sum= l1.val +carry;
l1=l1.next;
}elseif(l2 !=null){
sum= l2.val +carry;
l2=l2.next;
}else{
sum=carry;if(sum == 0)
break;
}
p.next=newListNode(sum % 10);
carry= sum / 10;
p=p.next;
}returnnode.next;
}publicstaticvoidmain(String[] args) {//TODO Auto-generated method stub}
}