(学习java)哈夫曼树的简单实现

package myhuffman;//哈夫曼树结点的建立public class TreeNode {//结点数据private Object data;//结点权值private int count;private TreeNode lchild;private TreeNode rchild;public TreeNode(){}public TreeNode(Object data,int count){this.data = data;this.count = count;}public TreeNode(int count, TreeNode lchild,TreeNode rchild){this.count = count;this.lchild = lchild;this.rchild = rchild;data = null;}public Object getData() {return data;}public void setData(Object data) {this.data = data;}public int getCount() {return count;}public void setCount(int count) {this.count = count;}public TreeNode getLchild() {return lchild;}public void setLchild(TreeNode lchild) {this.lchild = lchild;}public TreeNode getRchild() {return rchild;}public void setRchild(TreeNode rchild) {this.rchild = rchild;}}

哈夫曼树类

package myhuffman;import java.util.ArrayList;//哈夫曼树的实现public class HuffmanTree {private TreeNode root;private ArrayList<String> list; // 存储不同字符的队列,相同的字符在同一位置private ArrayList<TreeNode> nodeList; // 存储结点的队列// 将字符串中的字符分类分类public void createHuffmanTree(String s) {list = new ArrayList<String>();nodeList = new ArrayList<TreeNode>();// 将字符串中相同的字符找出来合并到一起,添加到集合中for (int i = 0; i < s.length(); i++) {// 判断字符是否在集合中存在的标签,若存在则置为falseboolean flag = true;char ch = s.charAt(i);for (int j = 0; j < list.size(); j++) {// 遍历集合,如果ch在集合中,则将其加入该集合中if (ch == list.get(j).charAt(0)) {String str = list.get(j) + ch;list.set(j, str);flag = false;break;}}if (flag) {// 如果集合中不存在该字符,则将其添加到集合中list.add(ch + "");}}// 创建结点,将其添加到nodeList集合中for (int i = 0; i < list.size(); i++) {String str = list.get(i);// 创建结点对象TreeNode node = new TreeNode(str.charAt(0) + "", str.length());nodeList.add(node);}// 将nodeList中的元素权限由小到排序nodeList = Sort(nodeList);// 当nodeList中元素不为1个时,将最小的两个结点依次取出,合并成新的结点,并将新结点添加到nodeList的首位置while (nodeList.size() > 1) {// 将第一个取出的结点定义为右孩子结点TreeNode rchild = nodeList.remove(0);TreeNode lchild = nodeList.remove(0);int count = lchild.getCount() + rchild.getCount();// 利用TreeNode的第二种构造方法,将parent创建出来,其左右子树分别指向最小的两个结点TreeNode parent = new TreeNode(count, lchild, rchild);// 将新结点添加到nodeList的首位置nodeList.add(0, parent);}// 将最后剩下的结点赋值给rootroot = nodeList.get(0);}// 将nodeList中的元素权限由小到排序private ArrayList<TreeNode> Sort(ArrayList<TreeNode> nodeList) {ArrayList<TreeNode> newNodeList = new ArrayList<TreeNode>();while(nodeList.size()>0){TreeNode min = nodeList.get(0);for (int i = 1; i < nodeList.size(); i++) {if(min.getCount()>nodeList.get(i).getCount()){min = nodeList.get(i);}}newNodeList.add(min);nodeList.remove(min);}return newNodeList;}//遍历哈弗曼二叉树public void List(){HUFMList(root);}private void HUFMList(TreeNode node){if(node.getLchild()!=null){visit(node.getLchild());}else{node = node.getRchild();}node = node.getRchild();if(node.getRchild() == null){visit(node);return;}HUFMList(node);}private void visit(TreeNode lchild) {System.out.println(lchild.getCount()+"--" + lchild.getData());}}

测试类

package myhuffman;public class HuffmanTreeDemo {public static void main(String[] args) {HuffmanTree ht = new HuffmanTree();ht.createHuffmanTree("acacdewafdsbnmafad");ht.List();}}