First~~~~

//树的节点类

public class NodeTree {

public NodeTree left;

public NodeTree right;

public NodeTree parents;

public NodeData data;

//用构造器直接传入数据

public NodeTree(NodeData data){

this.data = data;

}

}

Second~~~~

//数据类

public class NodeData {

public char s;

public int weight;

}

Third~~~~~

//哈弗曼树的建立

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

public class TreeHFM {

//创建HFM树，并返回根节点

public NodeTree creatHFM(List<NodeTree> node){

NodeTree tem = null;

//1排序 2更新队列 3算法

while(!(node.size()<2)){

sort(node);//队列排序 从小到大

NodeTree a1 = node.remove(0);//取得最小的两个元素

NodeTree a2 = node.remove(0);

//建树

NodeData da = new NodeData();//节点对象的数据

da.weight = a1.data.weight+a2.data.weight;

NodeTree root = new NodeTree(da);//创建节点对象

root.left = a1;

root.right = a2;

a1.parents = root;

a2.parents = root;

node.add(root);//将节点放入队列

tem=root;

}

return tem;

}

//排序 从小到大 冒泡

public void sort(List<NodeTree> node){

for(int i=0;i<node.size();i++){

NodeTree i1 = node.get(i);

for(int j=i+1;j<node.size();j++){

NodeTree j1 = node.get(j);

if(i1.data.weight > j1.data.weight){//如果i1小于j1，则交换

NodeTree temp = node.get(i);

node.set(i, node.get(j));

node.set(j, temp);

}

}

}

}

//获得哈弗曼编码 返回 数据NodeData 与 编码String 形成映射的Map

public Map<NodeData,String> creatCode(NodeTree root,String code){

java.util.Map<NodeData,String> ma = new java.util.HashMap<NodeData,String>();

if(root.left!=null){//根节点的左子树不为空，+1 到码表中

ma.putAll(creatCode(root.left,code+”1″));

}

if(root.right!=null){//根节点的右子树不为空，+0到码表中

ma.putAll(creatCode(root.right,code+”0″));

}

if((root.right==null)&&(root.left==null)){//如果是叶子节点，返回码表

ma.put(root.data, code);

}

return ma;

}

//遍历打印树 格式 (char)a 011

public void printHFM(NodeTree root){//,Map<NodeData,String> ma

if(root!=null){//先序排列

System.out.println(root.data.weight);

NodeTree left = root.left;

printHFM(left);

NodeTree right = root.right;

printHFM(right);

}

}

//生成一个模拟数据 返回 存放树节点的队列

public List<NodeTree> datacreat(){

List<NodeTree> node = new ArrayList<NodeTree>();

for(int i=0;i<10;i++){

NodeData da = new NodeData();

da.s = (char)(97+i);

da.weight = (10-i)*2;

NodeTree no = new NodeTree(da);

node.add(no);

}

return node;

}

public static void main(String[] args) {

TreeHFM tr = new TreeHFM();

List<NodeTree> node = tr.datacreat();

NodeTree root = tr.creatHFM(node);

tr.printHFM(root);

//遍历码表

String code = “”;

java.util.Map<NodeData,String> ma = tr.creatCode(root, code);

java.util.Set<NodeData> se = ma.keySet();

java.util.Iterator<NodeData> it = se.iterator();

while(it.hasNext()){

NodeData no = it.next();

String code1 = ma.get(no);

System.out.println(“字节是：”+no.s + ” weight是：”+no.weight +”码表为：”+code1);

}