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2 Add Two Numbers

LeetCode

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example 1:

Input: l1 = [2,4,3], l2 = [5,6,4] Output: [7,0,8] Explanation: 342 + 465 = 807.

Example 2:

Input: l1 = [0], l2 = [0] Output: [0]

Example 3:

Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9] Output: [8,9,9,9,0,0,0,1]

Constraints:

The number of nodes in each linked list is in the range [1, 100]. 0 <= Node.val <= 9 It is guaranteed that the list represents a number that does not have leading zeros.


/**
* 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 ret,p;
int carry=0;
ret=new ListNode((l1.val+l2.val)%10);
p=ret;
carry=(l1.val+l2.val)/10;
l1=l1.next; l2=l2.next;
while(l1!=null && l2!=null){
p.next=new ListNode((l1.val+l2.val+carry)%10);
p=p.next;
carry=(l1.val+l2.val+carry)/10;
l1=l1.next; l2=l2.next;
}
while(l1!=null){
p.next=new ListNode((l1.val+carry)%10);
p=p.next;
carry=(l1.val+carry)/10;
l1=l1.next;
}
while(l2!=null){
p.next=new ListNode((l2.val+carry)%10);
p=p.next;
carry=(l2.val+carry)/10;
l2=l2.next;
}
if(carry==1)
p.next=new ListNode(1);
return ret;
}
}