优先级队列实现哈夫曼树的编码和译码

//优先级队列实现的哈夫曼树的编码和译码

#include<iostream>
#include<queue>
#include<string>
using namespace std;

class Node
{
public:
float weight;
Node* left;
Node* right;
char ch;

Node(float w,Node* l=NULL,Node* r=NULL,char c=' '):weight(w),ch(c),left(l),right(r) {}
Node(float w,char c=' '):weight(w),ch(c),left(NULL),right(NULL) {}
};

class cmp
{
public :
bool operator()(Node* a,Node* b)
{
return a->weight>b->weight;
}
};

vector<int> v;
void Encode(Node* r)//打印字符的编码
{
if(r->left==NULL && r->right==NULL)
{
cout << r->ch <<": ";
for (int i = 0;i<v.size();++i)
cout << v[i];
cout << endl;
v.pop_back();
return ;
}
if(r->left)
{
v.push_back(0);
Encode(r->left);
}
if(r->right)
{
v.push_back(1);
Encode(r->right);
}
if(!v.empty())
{
v.pop_back();
}
}

void Decode(Node* root, string s)//译码
{
Node* p=root;
for(int i=0;i<s.length();++i)
{
if(s[i]=='0')
{
if(p->left) p=p->left;
else
{
cout<<s<<" Can't decode!"<<endl;
return ;
}
}
if(s[i]=='1')
{
if(p->right) p=p->right;
else
{
cout<<s<<" Can't decode!"<<endl;
return ;
}
}
}
cout<<s<<": "<<p->ch<<endl;
}

void freeTree(Node* p)//销毁哈夫曼树
{
if(p->left!=NULL)
freeTree(p->left);
if(p->right!=NULL)
freeTree(p->right);
delete p;
p=NULL;
}

int main()
{
Node* m1,*m2;
char ch[]={'A','C','E','D','F','G'};//字符
float f[]={0.1,0.3,0.4,0.5,0.2,0.6};//频率

priority_queue<Node*,vector<Node*>,cmp> q;
int n=sizeof(ch)/sizeof(ch[0]);
for(int i=0;i<n;++i)
{
q.push(new Node(f[i],ch[i]));
cout<<ch[i]<<": "<<f[i]<<'\t';
}
cout<<endl;
for(int i=1;i<n;++i)
{
m1=q.top(); q.pop();
m2=q.top(); q.pop();
float w=m1->weight+m2->weight;
q.push(new Node(w,m1,m2));
}
Node* root=q.top();
Encode(root);
cout<<endl;
Decode(root,"1011");
freeTree(root);

return 0;
}