程式語言 - LeetCode - C - 2. Add Two Numbers

參考資訊：
https://www.cnblogs.com/grandyang/p/4129891.html

題目：


解答：

struct ListNode* addTwoNumbers(struct ListNode *l1, struct ListNode *l2)
{
    int carry = 0;
    struct ListNode *r = malloc(sizeof(struct ListNode));
    struct ListNode *cur = r;

    r->val = 0;
    r->next = NULL;
    while (l1 || l2) {
        int v1 = l1 ? l1->val : 0;
        int v2 = l2 ? l2->val : 0;
        int sum = v1 + v2 + carry;
        carry = sum / 10;

        cur->next = malloc(sizeof(struct ListNode));
        cur->next->val = sum % 10;
        cur->next->next = NULL;
        cur = cur->next;

        if (l1) {
            l1 = l1->next;
        }
        if (l2) {
            l2 = l2->next;
        }
    }

    if (carry) {
        cur->next = malloc(sizeof(struct ListNode));
        cur->next->val = 1;
        cur->next->next = NULL;
    }
    return r->next;
}