LeetCode 2. 两数相加

2. 两数相加

解题思路

初始化一个「空链表」，每次循环，向该链表末尾添加节点（保存当前个位数）

参考代码

class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode dummy = new ListNode(0);
        ListNode cur = dummy;
        int carry = 0;
        
        while(l1 != null || l2 != null || carry != 0) {
            int val1 = (l1 == null) ? 0 : l1.val;
            int val2 = (l2 == null) ? 0 : l2.val;
            int sum = val1 + val2 + carry;
            carry = sum / 10;
            cur.next = new ListNode(sum % 10);
            cur = cur.next;
            if(l1 != null) {
                l1 = l1.next;
            }
            if(l2 != null) {
                l2 = l2.next;
            }
        }
        return dummy.next;
    }
}