ARTS-Week001

Algorithm

本周Leetcode算法题:

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 contain a single digit. Add the two numbers and return it as a linked list.

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

Example:

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)

Output: 7 -> 0 -> 8

Explanation: 342 + 465 = 807.

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/add-two-numbers
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解答详情 :

/**

- Definition for singly-linked list.
- public class ListNode {
- int val;
- ListNode next;
- ListNode(int x) { val = x; }
- }
  */
class Solution {
	public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
    	ListNode before = new ListNode(0);
		ListNode now = before;

		int carry = 0;
		while(null != l1 || null != l2){
    		int x = null != l1 ? l1.val : 0;
    		int y = null != l2 ? l2.val : 0;

            int sum = x + y + carry;

            carry = sum / 10;
            sum = sum % 10;

            now.next = new ListNode(sum);

            now = now.next;
            if(null != l1){
                l1 = l1.next;
            }
            if(null != l2){
                l2 = l2.next;
            }
        }
        if(carry > 0){
            now.next = new ListNode(carry);
        }
        return before.next;
        }
}