/** * 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) {        ListNode *res = new ListNode(-1);        ListNode *cur = res;        int carry = 0;        while (l1 || l2) {            int n1 = l1 ? l1->val : 0;            int n2 = l2 ? l2->val : 0;            int sum = n1 + n2 + carry;            carry = sum / 10;            cur->next = new ListNode(sum % 10);            cur = cur->next;            if (l1) l1 = l1->next;            if (l2) l2 = l2->next;        }        if (carry) cur->next = new ListNode(1);        return res->next;    }};

我可能是个傻子，本来都给我逆序写好了，我偏要列表反转一下，mdzz

既然写了也要贴出来

ListNode* reverseList(ListNode *l){         ListNode *res = l;        ListNode *head = l->next;        ListNode *cur = head;        res->next = NULL;                                               while(head){            cur = head->next;            head->next = res;            res = head;            head = cur;        }        return res;    }

——