if(p->next->data<q->data){pre=q;q=p->next;}解释一下这句代码
时间: 2024-05-23 15:14:26 浏览: 4
这句代码是C语言中的一个if语句,其条件为"p指针所指向的节点的下一个节点的数据小于q指针所指向的节点的数据"。如果条件成立,那么执行if语句中的两个语句:将q指针指向p指针所指向的节点的下一个节点,将pre指针指向p指针所指向的节点。这段代码常用于链表排序中,目的是找出当前链表中最小的节点,并将其插入到已排序部分的末尾。
相关问题
DLinkNode *pre=p->prior; e=p->data; if (p->next) { p->next->prior=pre; pre->next=p->next; free(p); return 1; } else { pre->next=NULL; free(p); return 1;
这是一个双向链表中删除节点的代码,其中p为要删除的节点指针,e为要删除的节点的数据。如果p的下一个节点存在,则将其前驱节点的next指向p的下一个节点,将p的下一个节点的前驱指向p的前驱节点,然后释放p节点并返回1;否则,将p的前驱节点的next指向NULL,释放p节点并返回1。
void deletes(LinkList *h,int min,int max) { LinkList *p = h->next, *q, *pre = h, *s; while(p&&p->data<=min) {//查找第一个大于min的结点 pre = p; p = p->next; } if(p) { while(p&&p->data<max) { //查找第一个大于max的结点 p = p->next; } q = pre->next; pre->next = p;//修改指针 while(q!=p) {//释放结点空间 s = q->next; free(q); q = s; } } }的时间复杂度和空间复杂度分析
!= NULL) { if(p->data >= min && p->data <= max) { q = p; pre->next = q->next; p = p->next; free(q); } else { pre = p; p = p->next; } } }
This function deletes all nodes in a linked list whose data values fall within a given range (min to max inclusive). It uses four pointers - p, q, pre, and s - to traverse the list and delete nodes as necessary.
The function takes in a pointer to the head node of the list as its first argument, and the minimum and maximum values for the range as its second and third arguments, respectively.
The while loop continues iterating through the list until p reaches the end (i.e., p == NULL). Inside the loop, the function checks whether the data value of the current node (p->data) falls within the given range. If it does, the node is deleted by setting q to point to the current node, updating the previous node's next pointer (pre->next) to skip over the current node, and freeing the memory used by the current node (using the standard library function free()).
If the current node's data value does not fall within the given range, the function simply updates pre and p to point to the next nodes in the list.
Once the loop finishes, all nodes whose data values fall within the given range should have been removed from the list.