1.哈弗曼树的节点声明
1 package com.neusoft.Tree;
2
3 public class HuffmanNode {
4 public int weight;
5 //加入哈夫曼树的标志，flag=0表示该节点没有加入哈夫曼树，=1表示加入
6 public int flag;
7 public HuffmanNode parent,lchild,rchild;
8 public HuffmanNode() {
9 this(0);
10 }
11 public HuffmanNode(int weight){
12 this.weight=weight;
13 flag=0;
14 parent=lchild=rchild=null;
15 }
16 }
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1 package com.neusoft.Tree;
2
3 public class HuffmanNode {
4 public int weight;
5 //加入哈夫曼树的标志，flag=0表示该节点没有加入哈夫曼树，=1表示加入
6 public int flag;
7 public HuffmanNode parent,lchild,rchild;
8 public HuffmanNode() {
9 this(0);
10 }
11 public HuffmanNode(int weight){
12 this.weight=weight;
13 flag=0;
14 parent=lchild=rchild=null;
15 }
16 }
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2.哈夫曼编码的构建及测试
1 package com.neusoft.Tree;
2 /**
3 * @author zhao-chj
4 * 哈夫曼树及其操作
5 */
6 public class HuffmanTree {
7
8 //求哈夫曼编码的算法，w存放n个字符的权值
9 public int[][] huffmanCoding (int[] w){
10 int n= w.length;//哈夫曼树的字符个数
11 int m=2*n-1;//哈夫曼树的节点个数
12 HuffmanNode[] HN =new HuffmanNode[m];
13 int i=0;
14 for (i = 0; i< n; i++) {
15 HN[i] = new HuffmanNode(w[i]);//构造n个具有权值的节点
16 }
17 for (i = n; i< m; i++) {
18 HuffmanNode min1=selectMin(HN,i-1);
19 min1.flag=1;//表示已标记
20 HuffmanNode min2=selectMin(HN, i-1);
21 min2.flag=1;
22 //构造min1和min2的父节点，并且修改权值
23 HN[i] =new HuffmanNode();
24 min1.parent=HN[i];
25 min2.parent=HN[i];
26 HN[i].lchild=min1;
27 HN[i].rchild=min2;
28 HN[i].weight=min1.weight+min2.weight;
29 }
30 //从叶子节点到根逆向求每个字符的哈夫曼编码
31 int[][] HuffCode =new int[n][n];//分配n个字符编码存储空间
32 for (int j = 0; j <n; j++) {
33 int start=n-1;//编码的开始位置，初始化为数组的结尾
34 for (HuffmanNode c=HN[j],p=c.parent; p!=null; c=p,p=p.parent) {
35 //从叶子结点到根逆向求解编码
36 if (p.lchild.equals(c)) {//左孩子编码为0
37 HuffCode[j][start--] =0;
38 }else {
39 //右孩子编码为1
40 HuffCode[j][start--]=1;
41 }
42 HuffCode[j][start]=-1;//编码的开始标志为-1
43 }
44 }
45 return HuffCode;
46 }
47 /**
48 * 在HN[0...i-1]选择不再哈夫曼树中且weight最小的节点
49 */
50 private HuffmanNode selectMin(HuffmanNode[] HN, int end) {
51 HuffmanNode min=HN[end];
52 for (int i = 0; i < end; i++) {
53 HuffmanNode h=HN[i];
54 if (h.flag==0&&h.weight<min.weight) {
55 //不再哈夫曼树中且weight最小的节点
56 min=h;
57 }
58 }
59 return min;
60 }
61 public static void main(String[] args) {
62 int [] w={23,11,5,3,29,14,7,8};
63 HuffmanTree T =new HuffmanTree();//构造哈夫曼树
64 int [][] HN=T.huffmanCoding(w);//求哈夫曼编码
65 System.out.println("哈夫曼编码为：");
66 for (int i = 0; i < HN.length; i++) {
67 System.out.print(w[i]+" ");
68 for (int j = 0; j < HN[i].length; j++) {
69 if (HN[i][j] ==-1 ) {//数组结尾标志
70 for (int k = j+1; k < HN[i].length; k++) {
71 System.out.print(HN[i][k]);
72 }
73 break;
74 }
75 }
76 System.out.println();
77 }
78 }
79 }
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1 package com.neusoft.Tree;
2 /**
3 * @author zhao-chj
4 * 哈夫曼树及其操作
5 */
6 public class HuffmanTree {
7
8 //求哈夫曼编码的算法，w存放n个字符的权值
9 public int[][] huffmanCoding (int[] w){
10 int n= w.length;//哈夫曼树的字符个数
11 int m=2*n-1;//哈夫曼树的节点个数
12 HuffmanNode[] HN =new HuffmanNode[m];
13 int i=0;
14 for (i = 0; i< n; i++) {
15 HN[i] = new HuffmanNode(w[i]);//构造n个具有权值的节点
16 }
17 for (i = n; i< m; i++) {
18 HuffmanNode min1=selectMin(HN,i-1);
19 min1.flag=1;//表示已标记
20 HuffmanNode min2=selectMin(HN, i-1);
21 min2.flag=1;
22 //构造min1和min2的父节点，并且修改权值
23 HN[i] =new HuffmanNode();
24 min1.parent=HN[i];
25 min2.parent=HN[i];
26 HN[i].lchild=min1;
27 HN[i].rchild=min2;
28 HN[i].weight=min1.weight+min2.weight;
29 }
30 //从叶子节点到根逆向求每个字符的哈夫曼编码
31 int[][] HuffCode =new int[n][n];//分配n个字符编码存储空间
32 for (int j = 0; j <n; j++) {
33 int start=n-1;//编码的开始位置，初始化为数组的结尾
34 for (HuffmanNode c=HN[j],p=c.parent; p!=null; c=p,p=p.parent) {
35 //从叶子结点到根逆向求解编码
36 if (p.lchild.equals(c)) {//左孩子编码为0
37 HuffCode[j][start--] =0;
38 }else {
39 //右孩子编码为1
40 HuffCode[j][start--]=1;
41 }
42 HuffCode[j][start]=-1;//编码的开始标志为-1
43 }
44 }
45 return HuffCode;
46 }
47 /**
48 * 在HN[0...i-1]选择不再哈夫曼树中且weight最小的节点
49 */
50 private HuffmanNode selectMin(HuffmanNode[] HN, int end) {
51 HuffmanNode min=HN[end];
52 for (int i = 0; i < end; i++) {
53 HuffmanNode h=HN[i];
54 if (h.flag==0&&h.weight<min.weight) {
55 //不再哈夫曼树中且weight最小的节点
56 min=h;
57 }
58 }
59 return min;
60 }
61 public static void main(String[] args) {
62 int [] w={23,11,5,3,29,14,7,8};
63 HuffmanTree T =new HuffmanTree();//构造哈夫曼树
64 int [][] HN=T.huffmanCoding(w);//求哈夫曼编码
65 System.out.println("哈夫曼编码为：");
66 for (int i = 0; i < HN.length; i++) {
67 System.out.print(w[i]+" ");
68 for (int j = 0; j < HN[i].length; j++) {
69 if (HN[i][j] ==-1 ) {//数组结尾标志
70 for (int k = j+1; k < HN[i].length; k++) {
71 System.out.print(HN[i][k]);
72 }
73 break;
74 }
75 }
76 System.out.println();
77 }
78 }
79 }
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3.测试及运行结果
时间： 2024-10-21 01:41:25