Question

编写算法,在带表头界点的单链表中,实现在p指针所指向的结点前插入一个元素x

Answer 1

假定单链表类型为queue， 元素x的类型为type，节点类型也为queue

queue* insert(queue* head, queue* p, type x)
{
queue* tmpUnit = (queue*)malloc(sizeof(queue));
queue* pre = head;
tmpUnit->value = x;
tmpUnit->next = NULL;
if(NULL == pre)
return head = tmpUnit;
while(pre->next && pre != p)
{
pre = pre->next;
}
tmpUnit->next = pre->next;
pre->next = tmpUnit;
return head;
}