LeetCode #2 Add Two Numbers

最新推荐文章于 2025-08-16 00:47:01 发布

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本文介绍了一种解决两个链表表示的非负整数相加的方法。通过遍历链表节点并考虑进位，实现了链表形式的加法运算。

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题目原文

You are given two linked lists representing two non-negative numbers.
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.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4) Output: 7 -> 0 -> 8

题目的意思是对两个非负整数求和，两个非负整数分别按位存储在链表中。
直接列竖式计算就好了，注意进位的保存。

提交代码

ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
       int over=0;
    ListNode *out;
    int t = l1->val + l2->val;
    if(t<10)
    {
        out = new ListNode(t);
        over=0;
    }
    else
    {
        out = new ListNode(t%10);
        over = 1;
    }
    ListNode *out_next = out;
    ListNode *out_end = out;
    t=0;
    while(l1->next||l2->next)
    {
        if(l1->next)
        {
            l1 = l1->next;
            t += l1->val;
        }
        if(l2->next)
        {
            l2 = l2->next;
            t += l2->val;
        }
        t += over;
        if(t<10)
        {
            out_next->next = new ListNode(t);
            over = 0;
        }
        else
        {
            out_next->next = new ListNode(t%10);
            over = 1;
        }
        out_next = out_next->next;
        out_end = out_next;
        t=0;
    }
    if(over == 1)
    {
        out_end->next = new ListNode(1);
    }
    return out;
    }