LintCode-167.链表求和

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;      
 *     }
 * }
 */
public class Solution {
    /**
     * @param l1: the first list
     * @param l2: the second list
     * @return: the sum list of l1 and l2 
     */
    public ListNode addLists(ListNode l1, ListNode l2) {
        // write your code here
        int carry = 0;
        int sum = l1.val + l2.val;
        ListNode n1 = l1.next;
        ListNode n2 = l2.next;
        ListNode head = new ListNode(sum%10);
        ListNode temp = head;
        sum /= 10;
        while(n1 != null || n2 != null || sum != 0){
            sum +=(((n1 == null) ? 0 : n1.val) + ((n2 == null) ? 0 : n2.val));
            temp.next = new ListNode(sum%10);
            temp = temp.next;
            n1=((n1 == null) ? null : n1.next);
            n2=((n2 == null) ? null : n2.next);
            sum /= 10;
        }
        return head;
    }
}