面试题13—在O（1）时间删除链表结点

题目：给定单链表的头指针和一个结点指针，在O(1)时间删除该结点。

代码示例：

#include<iostream>
using namespace std;
template < typename T >
struct Node
{
	T data;
	Node *next;
};
template < typename T >
class LinkList
{
	Node<T> *head;
public:
	LinkList()
	{
		head = new Node<T>();
		head->next = NULL;
	}
	~LinkList();
	void CreateList(T a[], int n);
	void Disp(void);
	void DeleteOneNode(Node<T> *node);
	Node<T> *GetOneNode(int index);//得到编号为index的结点
};

template<typename T>
LinkList<T>::~LinkList()
{
	Node<T> *pre = head;
	Node<T> *p = head->next;
	while (p)
	{
		delete pre;
		pre = p;
		p = p->next;
	}
	delete pre;
}
template<typename T>
void LinkList<T>::CreateList(T a[], int n)
{
	Node<T> *p = head;

	for (int i = 0; i < n; i++)
	{
		Node<T> *q = new Node<T>();
		q->data = a[i];

		p->next = q;
		p = q;
	}
	p->next = NULL;
}
template<typename T>
void LinkList<T>::Disp()
{
	Node<T> *p = head->next;
	while (p != NULL)
	{
		cout << p->data << " ";
		p = p->next;
	}
	cout << endl;
}
template<typename T>
void LinkList<T>::DeleteOneNode(Node<T> *node)
{
	//===
	if (head->next == NULL)
		return;
	//===
	if (node->next == NULL)
	{
		Node<T> *p = head;
		while (p->next != node)
			p = p->next;

		delete node;
		p->next = NULL;
		return;
	}
	//===
	Node<T> *p = node->next;
	node->data = p->data;
	node->next = p->next;
	delete p;
}

template<typename T>
Node<T> *LinkList<T>::GetOneNode(int index)
{
	Node<T> *p = head;
	if (index == 0)
		return p;
	for (int i = 0; i < index; i++)
	{
		p = p->next;
	}
	return p;
}
void main()
{
	const int n = 3;
	int a[n] = { 5,6,9 };
	LinkList<int> list;
	list.CreateList(a, n);
	list.Disp();
	//===
	int index = 1;
	Node<int>*p = list.GetOneNode(index);
	list.DeleteOneNode(p);
	list.Disp();
}