C++实现哈夫曼编码

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
using namespace std;

int Max = 300;

class tree{
	public:
		char s;
		int num;
		tree *left;
		tree *right;
		tree(){
			s= '!';
			num = 0;
			left = 0;
			right = 0;
		}
		tree(char a,int n,tree* p1,tree* p2){
			s = a;
			num = n;
			left = p1;
			right = p2;
		}
};

vector<tree *> open;

/*********************************
**中序遍历输出各节点及其哈夫曼编码
*********************************/ 
void inorder(tree *t,string s){
	if(t != 0){
		inorder(t->left,s+'0');
		if(t->s != '!')
			cout<<t->s<<":"<<s<<endl;
		inorder(t->right,s+'1');
	}
}


int main(){
	int a[Max];
	for(int i = 0;i < Max;i++)
		a[i] = 0;			//初始化数组 
	string s;
	cout<<"请输入字符串：";
	cin>>s;
	
	vector<char> v;
	vector<char>::iterator vit;
	for(int i = 0;i < s.length();i ++){
		a[s[i]]++;			//确定每个字符出现的次数（频率） 
		vit = find(v.begin(),v.end(),s[i]);
		if(vit == v.end())	//相同的字符只保留一个 
			v.push_back(s[i]);
	}
	for(int i = 0;i < v.size();i ++){
		tree *n = new tree();
		n->s = v[i];
		n->num = a[v[i]];
		open.push_back(n);	//存入open表中 
	}
	
	/************************
	**
	**构造哈夫曼树 
	**
	*************************/ 
	tree *root;
	while(open.size() != 1){
		tree *min1,*min2;	//min1,min2是当前open表中num值最小的节点 
		int sit1,sit2;
		min1 = open.front();
		sit1 = 0;
		for(int i = 0;i < open.size();i++){
			if(open[i]->num < min1->num){
				min1 = open[i];
				sit1 = i;
			}
		}
		open.erase(open.begin()+sit1);
		
		min2 = open.front();
		sit2 = 0;
		for(int i = 0;i < open.size();i++){
			if(open[i]->num < min2->num){
				min2 = open[i];
				sit2 = i;
			}
		}
		open.erase(open.begin()+sit2);
		
		tree *t = new tree('!',min1->num + min2->num,min1,min2); //构造新节点，左右指针指min1和min2 
		open.push_back(t);	//存入open表中 
		root = t;
	}
	
	cout<<"它的哈夫曼编码为："<<endl;
	string s1 = "";
	inorder(root,s1);
	
	return 0;
}```