LeetCode——Add Two Numbers

最新推荐文章于 2025-12-19 16:34:09 发布

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本文介绍了一种解决两数相加问题的方法，通过链表形式存储数字，并以逆序方式排列各节点的数值。文章提供了一个简洁的C++代码示例，展示了如何将两个链表表示的非负整数相加，并返回结果作为新的链表。

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

» Solve this problem

这题比较简单，怎么想就怎么写。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        ListNode *head = NULL, *prev = NULL;
        int c = 0;
        while (l1 != NULL || l2 != NULL || c != 0) {
            if (l1 != NULL) {
                c += l1->val;
                l1 = l1->next;
            }
            if (l2 != NULL) {
                c += l2->val;
                l2 = l2->next;
            }
            ListNode *p = new ListNode(c % 10);
            if (head == NULL) {
                head = p;
            }
            else {
                prev->next = p;
            }
            prev = p;
            c /= 10;
        }
        return head;
    }
};