题目：

题解：

struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2){int stack1[100];int stack2[100];int top1 = 0;int top2 = 0;int carry = 0;int sum = 0;struct ListNode* temp = NULL;struct ListNode* head = NULL;while (l1) {stack1[top1++] = l1->val;l1 = l1->next;}while (l2) {stack2[top2++] = l2->val;l2 = l2->next;}while (top1 || top2 || carry) {int m = top1 > 0 ? stack1[--top1] : 0;int n = top2 > 0 ? stack2[--top2] : 0;sum = m + n + carry;carry = sum / 10;head = malloc(sizeof(struct ListNode));head->val = sum % 10;head->next = temp;temp = head;}return head;
}