题解 | #删除有序链表中重复的元素-I#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param head ListNode类 
 * @return ListNode类
 */
struct ListNode* deleteDuplicates(struct ListNode* head ) {
    // write code here
    if(head == NULL){
        return NULL;
    }
    struct ListNode* p=head->next;
    struct ListNode* pre=head;

    while (p!=NULL) {
        while(pre->val==p->val) {
            struct ListNode*  t=p;
            p=p->next;
            pre->next = t->next;
            free(t); 
            if (p==NULL) {
                return head;
            }
        }
        pre=pre->next;
        p=p->next;
        if (pre == NULL) {
            return head;
        }
    }
    
    return head;
}