广义表的简单实现
广义表：广义表是一种非线性数据结构，是线性表的推广。广义表是一种单递归的思想，它允许表中有表。
例：L=(); 空表，深度为1
L1=(()); 具有一个元素的广义表，深度为2
L2=(a，((f))，b) 具有三个元素，深度为3
广义表的存储：
现在我们来实现简单广义表的存储，允许表中的元素是字母或者数字。由于广义表中的元素有可能是数据项，也有可能是子表，但是只能是其中一个。所以我们在创建一个广义表的结点的时候可以将数据项和子表封装成一个联合体。此外还必须有一个指向下一个结点的指针。
例：L2的存储结构如图
#pragmaonce
#include<iostream>
#include<cassert>
using namespace std;
enum Type //广义表的结点有三种类型
{
HEAD_TYPE, //头结点
VALUE_TYPE, //值类型
LIST_TYPE, //表类型
};
struct GeneralizedNode
{
Type _type;
GeneralizedNode * _next; //指向下一个结点的指针
union //局部类，值或表
{
char _value; //值类型
GeneralizedNode* _sublink; //表类型
};
GeneralizedNode()
:_next(NULL)
, _sublink(NULL)
{}
};
class GeneralizedList
{
typedef GeneralizedNode Node;
public:
GeneralizedList()
{}
GeneralizedList(const char *str)
:_head(new Node)
{
_head=_CreatList(str,_head);
}
~GeneralizedList()
{
_destroy(_head);
}
GeneralizedList(const GeneralizedList& l) //拷贝构造函数
{
_head =NULL;
_head=_Copy(_head,l._head);
}
GeneralizedList& operator=(GeneralizedList l)
{
swap(_head,l._head);
return *this;
}
size_t Size()
{
return _Size(_head);
}
size_t Depth()
{
return _Depth(_head);
}
void Display()
{
_print(_head);
cout << endl;
}
private:
Node* _CreatList(const char* &str,Node *head=(new Node))
{
assert(*str=='(');
++str;
Node* prev= head;
head->_type = HEAD_TYPE;
while (*str)
{
if ((*str >= 'a'&&*str <= 'z')
|| (*str >= 'A'&&*str <= 'Z')
|| (*str >= '0'&&*str <= '9'))
{
prev->_next = new Node;
prev = prev->_next;
prev->_value = *str;
++str;
prev->_type = VALUE_TYPE;
}
else if (*str == '(')
{
prev->_next = new Node;
prev = prev->_next;
prev->_sublink= _CreatList(str); //遇到子表递归处理
prev->_type = LIST_TYPE;
++str;
}
else if (*str == ')')
{
return head;
}
else
{
++str;
}
}
return head;
}
void _print(Node* head)
{
assert(head);
Node *cur =head;
while (cur)
{
if (cur->_type ==VALUE_TYPE)
{
cout << cur->_value;
if (cur->_next != NULL) //如果不是最后一个值，则后面输出逗号
{
cout << ",";
}
cur = cur->_next;
}
else if (cur->_type==LIST_TYPE) //如果是子表
{
_print(cur->_sublink);
if (cur->_next != NULL) //如果不是最后一个值，则后面输出逗号
{
cout << ",";
}
cur = cur->_next;
}
else
{
cout << "(";
cur = cur->_next;
}
}
cout << ")";
}
size_t _Size(Node *head) //求广义表中数据的个数
{
size_t count = 0;
Node *cur = head;
while (cur)
{
if (cur->_type == VALUE_TYPE)
{
count++;
cur = cur->_next;
}
else if (cur->_type == LIST_TYPE)
{
count += _Size(cur->_sublink);
cur = cur->_next;
}
else
{
cur = cur->_next;
}
}
return count;
}
size_t _Depth(Node *head) //求广义表的深度
{
size_t MaxDeep =1;
size_t n =1;
Node *cur = head;
while (cur)
{
if (cur->_type == VALUE_TYPE)
{
cur = cur->_next;
}
else if (cur->_type == LIST_TYPE)
{
n+=_Depth(cur->_sublink);
if (n > MaxDeep)
{
MaxDeep = n;
}
n =1;
cur = cur->_next;
}
else
{
cur = cur->_next;
}
}
return MaxDeep;
}
Node* _Copy(Node *NewHead,Node* head)
{
assert(head);
Node *_newhead =new Node;
NewHead=_newhead;
Node *cur =head;
_newhead->_type = cur->_type; //设置头结点的类型
while (cur)
{
if (cur->_type == VALUE_TYPE)
{
_newhead->_next= new Node;
_newhead = _newhead->_next;
_newhead->_value= cur->_value;
_newhead->_type = cur->_type;
cur = cur->_next;
}
else if (cur->_type==LIST_TYPE)
{
_newhead->_next= new Node;
_newhead = _newhead->_next;
_newhead->_type = cur->_type;
_newhead->_sublink = _Copy(_newhead->_sublink,cur->_sublink); //对子表进行链接
cur = cur->_next;
}
else
{
cur = cur->_next;
}
}
return NewHead;
}
void _destroy(Node *head)
{
Node *del = head;
while (head)
{
del = head;
if (head->_type== LIST_TYPE)
{
_destroy(head->_sublink);
head = head->_next;
}
else
{
head = head->_next;
delete del;
}
}
}
protected:
Node *_head;
};
#include<iostream>
#include"GeneralizedList.h"
using namespace std;
void test()
{
GeneralizedList l="(a,(f,(d)),d)";
l.Display();
cout << l.Size() << endl;
cout << l.Depth() << endl;
GeneralizedList l2;
l2 = l;
l2.Display();
l.Display();
}
int main()
{
test();
system("pause");
return 0;
}
