Add Two Numbers

 

代码：

/**

 * Definition for singly-linked list.

 * public class ListNode {

 *     int val;

 *     ListNode next;

 *     ListNode(int x) {

 *         val = x;

 *         next = null;

 *     }

 * }

 */

public class Solution {

    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

              ListNode result = null;



        ListNode temp = null, node = null;

        int digit = 0, bit = 0;

        while (l1 != null && l2 != null) {

            digit = l1.val + l2.val + bit;

            bit = digit / 10;

            digit = digit % 10;

            node = new ListNode(digit);

            if (result == null) {

                result = node;

                temp = result;

            } else {

                temp.next = node;

                temp = temp.next;

            }

            l1 = l1.next;

            l2 = l2.next;

        }



        while (l1 != null) {

            digit = l1.val + bit;

            bit = digit / 10;

            digit = digit % 10;

            node = new ListNode(digit);

            if (result == null) {

                result = node;

                temp = result;

            } else {

                temp.next = node;

                temp = temp.next;

            }

            l1 = l1.next;

        }



        while (l2 != null) {

            digit = l2.val + bit;

            bit = digit / 10;

            digit = digit % 10;

            node = new ListNode(digit);

            if (result == null) {

                result = node;

                temp = result;

            } else {

                temp.next = node;

                temp = temp.next;

            }

            l2 = l2.next;

        }



        if (bit != 0) {

            node = new ListNode(bit);

            if (result == null) {

                result = node;

                temp = result;

            } else {

                temp.next = node;

                temp = temp.next;

            }

        }

        return result;

    }

}