力扣2. 两数相加

最新推荐文章于 2025-12-09 16:25:48 发布

原创最新推荐文章于 2025-12-09 16:25:48 发布 · 57 阅读

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#java

该代码实现了一个将两个非负整数表示为链表的节点，然后相加的功能。通过创建一个哑节点dummy作为新链表的头节点，逐位进行加法运算，并处理进位问题。最后返回新链表的头节点。

class Solution{
    public ListNode addTwoNumbers(ListNode l1, ListNode l2){
        if(l1 == null) return l2;
        if(l2 == null) return l1;
        ListNode dummy = new ListNode(0);
        ListNode current = dummy;
        int carry = 0;
        while(l1!=null && l2!=null){
            int digit = l1.val + l2.val + carry;
            carry = digit / 10;
            int val = digit % 10;
            ListNode newNode = new ListNode(val);
            current.next = newNode;
            current = current.next;
            l1 = l1.next;
            l2 = l2.next;
        }

        while(l1!=null){
            int digit = l1.val + carry;
            carry = digit / 10;
            int val = digit % 10;
            ListNode newNode = new ListNode(val);
            current.next = newNode;
            current = current.next;
            l1 = l1.next;
        }

        while(l2!=null){
            int digit = l2.val + carry;
            carry = digit / 10;
            int val = digit % 10;
            ListNode newNode = new ListNode(val);
            current.next = newNode;
            current = current.next;
            l2 = l2.next;
        }

        if(carry!=0) current.next = new ListNode(1);
        return dummy.next;
    }
}