【leetcode 简单】第十九题 删除排序链表中的重复元素

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* deleteDuplicates(struct ListNode* head) {
    if (head == NULL)
    {
        return NULL;
    }
    
    struct ListNode *p=head;
    struct ListNode *s=p->next;

    while(p->next != NULL)
    {
        if (p->val == s->val)
        {
            if (s->next != NULL)
                {
                    p->next = s->next;
                    s=s->next;
                }
                else
                {
                    p->next =NULL;
                    break;
                }
        }
        else
        {
            s=s->next;
            p=p->next;
        }
    }
    
    
     return head;
}