//可利用空間表
#include<iostream>
using namespace std;
template <class Elem> class Link{
 private:
    static Link<Elem>*freelist;
 public:
    Elem element;
    Link *next;
    Link(const Elem& elemval, Link *nextval=NULL)
     {element=elemval; next=nextval;}
    Link( Link *nextval=NULL)
     { next=nextval;}
  void *operator new(size_t);
  void  operator delete(void *);
};
template<class Elem>
Link<Elem>* Link<Elem>::freelist=NULL;

template<class Elem> 
void *Link<Elem>::operator new(size_t){
  if(freelist==NULL) return::new Link;
  Link<Elem>* temp=freelist;freelist=freelist->next;
   return  temp;
}

template<class Elem>
void Link<Elem>::operator delete(void *ptr)
{
   ((Link<Elem>*)ptr)->next=freelist;
    freelist=(Link<Elem>*)ptr;
}