用循環鏈表解決約瑟夫環問題

題目見http://poj.grids.cn/practice/2746/

解法：

#include<iostream>
using namespace std;

template<typename T>
struct Node
{
	T value;
	Node<T>* next;
	Node(T data,Node<T>* n=NULL):value(data),next(n){};
};

class NodeList
{
public:
	NodeList(int length):head(NULL),rear(NULL)
	{
		for(int i=1;i<=length;i++)	
		{
			Node<int>* node = new Node<int>(i);
			insert(node);
		}
	}

	void insert(Node<int> * newNode)
	{
		if(isEmpty())
		{
			newNode->next=newNode;
			head = newNode;
			rear = newNode;
		}
		else
		{
			newNode->next = head;
			rear->next = newNode;
			rear = newNode;
		}
	}

	Node<int>* josephusRemove(int interval)
	{
		Node<int> *p = head;
		Node<int> *q = rear;

		while(p->next!=p)
		{
			int count = 1;
			while(count < interval)
			{
				q = p;
				p = p->next;
				count++;
			}
			if(head==p) head = p->next;
			if(rear==p) rear = q;

			q->next=p->next;
			delete p;
			p = q->next;
		}

		return p;
	}


	bool isEmpty()
	{
		return head==NULL;
	}


	~NodeList()
	{			
		Node<int>* p = head;
		Node<int>* q;
		
		if(!isEmpty())
		{
			while(p->next!=head)
			{
				q = p;
				p = p->next;
				delete q;
			}
			delete p;
		}
	}

private:
	Node<int>* head;
	Node<int>* rear;
};

int main()
{
	int m,n;
	while(cin>>n>>m)
	{
		if(n==0&&m==0)break;
		NodeList list(n);
		Node<int>* p = list.josephusRemove(m);
		cout<<p->value<<endl;
	}
}