LeetCode-2. 两数相加-Java-medium

题目链接

法一

    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode head = new ListNode(0); // 带头结点的链表
        ListNode cursor = head;
        int sum = 0;
        while (l1 != null || l2 != null || sum != 0) {
            if (l1 != null) {
                sum += l1.val;
                l1 = l1.next;
            }
            if (l2 != null) {
                sum += l2.val;
                l2 = l2.next;
            }
            cursor.next = new ListNode(sum % 10);
            cursor = cursor.next;
            sum /= 10; // sum变为进位
        }
        return head.next;
    }
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本地测试

        /**
         * 2. 两数相加
         */
        lay.showTitle(2);
        Solution2 sol2 = new Solution2();
        ListNode head2_1 = new ListNode();
        ListNode head2_2 = new ListNode();
        int[] nums2_1 = new int[]{2,4,3};
        int[] nums2_2 = new int[]{5,6,4};
        head2_1 = listOpt.creatListByArray(head2_1, nums2_1);
        head2_2 = listOpt.creatListByArray(head2_2, nums2_2);
        listOpt.showList(head2_1);
        listOpt.showList(head2_2);
        ListNode head2 = sol2.addTwoNumbers(head2_1.next, head2_2.next);
        listOpt.showNoHeadList(head2);
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