1 import java.util.ArrayList;
2 import java.util.List;
3 import java.util.Map;
4 import java.util.Scanner;
5
6
7 class Node{
8 char letter;
9 int power;
10 Node left_son;
11 Node right_son;
12 public Node() { super();}
13 public Node(int power) {
14 this.power = power;
15 }
16 }
17 public class CurrDesign {
18
19 static Map<Character, String> map = new HashMap<Character, String>();
20 public static void main(String[] args) {
21 List <Node>list = codingTable();//输入
22 Node tree_root = creatHFMtree(list);
23 creatTable(tree_root,"");
24 display();
25
26 String text = inputText();
27 encode(text);
28
29 String code = inputCode();
30 decode(code,tree_root);
31 }
32
33 public static String[] encode(String text) {
34 String []s = new String[100];
35 char []key = text.toCharArray();
36 System.out.println("编码结果为：");
37 for(int i=0;i<key.length;i++) {
38 s[i]=map.get(key[i]);
39 System.out.print(s[i]+" ");
40 }
41 System.out.println();
42 return s;
43 }
44
45 public static void decode(String s,Node tree_root) {
46 System.out.println("译码结果为：");
47 char []num = s.toCharArray();
48 Node node = tree_root;
49 for(int i=0;i<num.length;i++) {
50 node = check(node,num[i]);
51 if(node==null) {
52 node = check(tree_root,num[i]);
53 }
54 }
55 System.out.println(node.letter);
56 }
57
58 public static Node check(Node node,char c) {
59 if(node.left_son!=null && c=='0')
60 return node.left_son;
61 else if(node.right_son!=null && c=='1'){
62 return node.right_son;
63 }
64 System.out.print(node.letter);
65 return null;
66 }
67
68 public static Object getKey(Object value){
69 for(Object key: map.keySet()){
70 if(map.get(key).equals(value)){
71 return key;
72 }
73 }
74 return null;
75 }
76
77 public static String inputText() {
78 Scanner in = new Scanner(System.in);
79 System.out.println("请输入要编码的文本，只含大写字母：");
80 String text = in.next();
81 return text;
82 }
83
84 public static String inputCode() {
85 Scanner in = new Scanner(System.in);
86 System.out.println("请输入编码：");
87 String code = in.next();
88 in.close();
89 return code;
90 }
91
92 public static List<Node> codingTable(){
93 List <Node>list = new ArrayList<Node>();
94 int []num = {186,64,13,22,32,103,21,15,47,57,1,2,32,20,57,63,15,1,48,51,80,23,8,18,1,16};
95 Node node = null;
96 for(int n=0;n<26;n++) {
97 node = new Node();
98 node.letter = (char)('A'+n);
99 node.power = num[n];
100 list.add(node);
101 }
102 return list;
103 }
104
105 public static void display() {
106 System.out.println("The huffman coding table are:");
107 System.out.println(map.toString());
108 }
109
110 public static Node creatHFMtree(List<Node> list){
111 Node p = null;
112 int n = 0;
113 while(!list.isEmpty()) {
114 if(n!=0) {
115 list.add(p);
116 }
117 Node min1 = new Node(1000);
118 Node min2 = new Node(999);
119 for(Node node:list) {
120 if(node.power < min1.power) {
121 if(node.power < min2.power) {
122 min1 = min2;
123 min2 = node;
124 }else {
125 min1 = node;
126 }
127 }
128 }
129 p = new Node(min1.power+min2.power);
130 p.left_son = min2;
131 p.right_son = min1;
132 list.remove(min1);
133 list.remove(min2);
134 n++;
135 }
136 return p;
137 }
138
139 public static void creatTable(Node node,String coding){
140 if(node.left_son!=null) {
141 creatTable(node.left_son,coding+"0");
142 }
143 if(node.right_son!=null) {
144 creatTable(node.right_son,coding+"1");
145 }
146 if(node.left_son==null && node.right_son==null) {
147 map.put(node.letter, coding);
148 }
149 }
150 }
