链表操作

////////////单链表///////////////
//定义节点
struct node
{
	int data;
    struct node *next;
};
typedef struct node NODE;


//申请节点并赋值
	NODE *ApplyNODE(int x)
	{
		NODE *p;
		p=(NODE *)malloc(sizeof(NODE));
		p->data=x;
		p->next=NULL;
        return (p);	
	}

//初始化链表
	NODE *InitList()
	{
		NODE *head;
		head=(NODE *)malloc(sizeof(NODE));
		head->next=NULL;
		return (head);	
	}

//将节点插入到链表
//(1)将节点p插入到链表头(p作为head之后的第一个元素，成为了新的表头节点)
	p->next=head->next;
	head->next=p;

//(2)将节点p插入到指定节点q之后
	p->next=q->next;
	q->next=p;

//(3)将节点p插入到链表尾
先找到链表的尾节点q:
	NODE *Searchrear(NODE *head)
	{
		NODE *q;
		q=head;
		while(q->next != NULL)
		{
			q=q->next;		
		}

		return (q);
	}
再将p节点插入到指定节点q的后面即可!


//头插法建立链表
NODE *CreateFromHead()
{
	NODE *head, *p, *q;
	int i, n, x;
	printf("\nInput the length of the line:");
	scanf("%d", &n);
	head=InitList();
	printf("\nInput %d datas:", n);
	for(i=0; i<n; i++)
	{
		scanf("%d", &x);
		p=applyNODE(x);
		p->next=head->next;
		head->next=p;
	}

	return (head);
}


//尾插法建立链表
NODE *CreatFromTail()
{
	NODE *head, *p, *q;
	int i, n, x;
	printf("\nInput the length of the line :");
	scanf("%d", &n);
	head=q=InitList();
	printf("\nInput %d datas:", n);
	for(i=0; i<n; i++)
	{
		scanf("%d", &x);
		p=applyNODE(x);
		q->next=p;
		q=p;
	}

	return (head);
}


//删除节点
//(1)删除给定节点p的后继节点, 用q记录要删除的节点
q=p->next;
p->next=q->next;
free(q); 

//(2)删除给定节点p
NODE *deletenode(NODE *head, NODE *p)
{
	NODE *q;
	q=head;
	while(q->next != p)
	{
		q=q->next;
	}
	q->next=p->next;
	free(p);

	return (head);
}

//输出单链表
void Display(NODE *head)
{
	NODE *p;
	printf("\nThe line are:");
	p=head->next;
	while(p != NULL)
	{
		printf("%d ", p->data);
		p=p->next;
	}
}

//查找给定值节点
NODE *Search(NODE *head, int x)
{
	NODE *p;
	p=head->next;
	while(p != NULL)&&(p->data != x)
	{
		p=p->next;
	}
    return (p);
}

////////////链表实现栈///////////////

//栈节点
struct node
{
	int data;
	struct node *next;
};
typedef struct node StackNode;
StackNode *top;

//初始化栈
StackNode *InitStack()
{
	NODE *top;
	top=(StackNode *)malloc(sizeof(StackNode));
	top->next=NULL;
	return (top);
}

//将x进栈
StackNode *Push(StackNode *top, DataType x)
{
	StackNode *p;
	p=(StackNode *)malloc(sizeof(StackNode));
	p->data=x;
	p->next=top->next;
	top->next=p;

	return (top);
}

//将栈顶元素出栈
StackNode *Pop(StackNode *top)
{
	StackNode *p;
	if(top->next == NULL)
	{
		printf(" 栈空，无法出栈");
		return(top);	
	}

	p=top->next;
	top->next=p->next;
	free(p);
	return (top);
}


////////////链表实现队列///////////////


//链队列节点
struct node
{
    int data;
	struct node *next;
};
typedef struct node QueueNode;

struct node2
{
	QueueNode *front;
	QueueNode *rear;
};
typedef struct node2 Queue;

//初始化队列
Queue InitQueue()
{
	Queue Q;
	Q.front=(QueueNode *)malloc(sizeof(QueueNode));
	Q.front->next=NULL;
	Q.rear=Q.front;
	return (Q);
}

//x进队列
Queue InsertQ(Queue Q, int x)
{
	QueueNode *p;
	p=(QueueNode *)malloc(sizeof(QueueNode));
	p->data=x;
	p->next=NULL;
	Q.rear->next=p;
	Q.rear=p;
    return (Q);
}

//出队列
Queue DeleteQ(Queue Q)
{
	QueueNode *p;
	if(Q.front == Q.rear)
	{
		printf("队列空，无法出队列!");
		return (Q);
	}
	p=Q.front->next;
	Q.front->next=p->next;
	if(p==Q.rear)
	{
		Q.rear=Q.front;	
	}

	free(p);
	return (Q);
}