从链表中删去总和值为零的连续节点(leetcode 1171)

class Solution {
public:
    ListNode* removeZeroSumSublists(ListNode* head) 
    {
        if (head == NULL) return NULL;
        ListNode* p = head;
        int sum = 0;

        while (p != NULL)
        {
            sum += p->val;
            p = p->next;
            if (sum == 0) return removeZeroSumSublists(p);
        }

        head->next = removeZeroSumSublists(head->next);

        return head;
    }
};