使用java构建一个哈夫曼树

使用java构建一个哈夫曼树

1. 定义节点类，表示哈夫曼树中的一个节点

代码：

class Node implements Comparable<Node> {char ch; // 字符int freq; // 频率Node left, right; // 左右子节点// 节点构造函数public Node(char ch, int freq, Node left, Node right) {this.ch = ch;this.freq = freq;this.left = left;this.right = right;}// 按频率比较节点@Overridepublic int compareTo(Node other) {return this.freq - other.freq;}
}

2. 构建哈夫曼树的方法

    public static Node buildHuffmanTree(char[] chars, int[] freq) {// 优先队列用于存储节点并按频率排序PriorityQueue<Node> pq = new PriorityQueue<>();// 创建节点并加入优先队列for (int i = 0; i < chars.length; i++) {pq.offer(new Node(chars[i], freq[i], null, null));}// 合并频率最低的节点构建哈夫曼树while (pq.size() > 1) {Node left = pq.poll();Node right = pq.poll();Node parent = new Node('\0', left.freq + right.freq, left, right);pq.offer(parent);}// 返回哈夫曼树的根节点return pq.poll();}

3. 主方法用于演示构建哈夫曼树

    public static void main(String[] args) {// 输入字符和频率char[] chars = {'a', 'b', 'c', 'd', 'e'};int[] freq = {3, 2, 4, 2, 1};// 构建哈夫曼树Node root = buildHuffmanTree(chars, freq);// 打印哈夫曼树结构printTree(root, "", true);System.out.println("Huffman Tree built successfully!");}

4. 递归打印哈夫曼树结构的方法

    public static void printTree(Node root, String prefix, boolean isLeft) {if (root != null) {System.out.println(prefix + (isLeft ? "├── " : "└── ") + root.ch + "(" + root.freq + ")");printTree(root.left, prefix + (isLeft ? "│   " : "    "), true);printTree(root.right, prefix + (isLeft ? "│   " : "    "), false);}}

5. 执行结果

├──  (12)
│   ├──  (5)
│   │   ├── b(2)
│   │   └──  (3)
│   │       ├── e(1)
│   │       └── d(2)
│   └──  (7)
│       ├── a(3)
│       └── c(4)
Huffman Tree built successfully!Process finished with exit code 0