习题11-8 单链表结点删除 (20 分)

struct ListNode *readlist(){
	struct ListNode *head=NULL,*rear=NULL,*p;
	int x;
	scanf("%d",&x);
	while(x!=-1){
		p=(struct ListNode *)malloc(sizeof(struct ListNode));
		p->data=x;
		if(head==NULL)
			head=rear=p;
		else{
			rear->next=p;
			rear=p;
			rear->next=NULL;
		}
		scanf("%d",&x);
	} 
	return head;
}//顺序输出使用尾插法

struct ListNode *deletem( struct ListNode *L, int m ){
	struct ListNode *q,*p;
	p=L;
	q=L;//使用双指针
	while(q){
		if(p==q){
			if(p->data!=m){
				q=p->next;
			}
			else{
				q=p->next;
				p->next=NULL;
				free(p);
				L=p=q;
			}
		}
		else{
			if(q->data!=m){
				p=p->next;
				q=q->next;
			}
			else{
				p->next=q->next;
				free(q);
				q=p->next;
			}
		}
	}
	return L;
}