实现哈夫曼树

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手写实现哈夫曼树的编码功能:

package com.example.admin.myapplication.tree;/** * 哈夫曼树 * Created by admin on 2017/11/16. */public class HuffmanTree {    private SortLinkQueue linkQueue;    public HuffmanTree() {        linkQueue = new SortLinkQueue();    }    /**     * 哈夫曼编码     * @param array     */    public void huffmanEncoding(int[] array) {        for (int value : array) {            linkQueue.add(createNode(value));        }        while (linkQueue.size() > 1) {            Node<Integer> l = linkQueue.offer();            l.code = 0;            Node<Integer> r = linkQueue.offer();            r.code = 1;            Node<Integer> compound = createNode(l.value + r.value);            compound.liftChild = l;            compound.rightChild = r;            linkQueue.add(compound);        }        traversal(linkQueue.offer());    }    /**     * 遍历哈夫曼数生成编码     * @param node     */    private void traversal(Node node) {        if (node == null) {            return;        }        if (node.liftChild != null) {            node.liftChild.encoding = node.encoding + node.liftChild.code;            traversal(node.liftChild);        }        if (node.rightChild != null) {            node.rightChild.encoding = node.encoding + node.rightChild.code;            traversal(node.rightChild);        }        if (node.liftChild == null && node.rightChild == null) {            System.out.println(node.value + " 编码为： " + node.encoding);        }    }    /**     * 创建一个节点     * @param value     * @return     */    private Node<Integer> createNode(int value) {        Node<Integer> node = new Node<>();        node.value = value;        return node;    }    /**     * 排序队列     */    class SortLinkQueue {        /**         * 指向队头         */        private Node<Integer> head;        /**         * 指向队尾         */        private Node<Integer> last;        int count = 0;        /**         * 取出并删除队首元素         *         * @return         */        Node<Integer> offer() {            if (count <= 0 || head == null) {                return null;            }            Node node = head;            head = head.next;            if (node.next != null) {                node.next.parent = null;                node.next = null;            }            count--;            return node;        }        /**         * 添加一个节点         *         * @param node         */        void add(Node<Integer> node) {            if (head == null) {                head = node;                last = node;            } else {                Node<Integer> n = head;                for (; n != null; ) {                    if (node.value > n.value) {                        n = n.next;                    } else {                        break;                    }                }                if (n != null) {//找到比添加值大的                    if (n.parent == null) {//头结点                        head = node;                        node.next = n;                        n.parent = node;                    } else {                        node.next = n;                        node.parent = n.parent;                        node.parent.next = node;                        n.parent = node;                    }                } else {                    last.next = node;                    node.parent = last;                    last = node;                }            }            count++;        }        int size() {            return count;        }    }    class Node<T> {        /**         * 编码         */        String encoding = "";        T value;        /**         * 编码，0左子树，1右子数         */        int code;        Node liftChild;        Node rightChild;        Node next;        Node parent;    }}

测试：

int[] dataArray = {23, 10, 15, 20, 50, 21, 8, 6, 13};HuffmanTree huffmanTree = new HuffmanTree();huffmanTree.huffmanEncoding(dataArray);

结果：

11-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 6 编码为： 000011-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 8 编码为： 000111-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 15 编码为： 00111-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 20 编码为： 01011-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 21 编码为： 01111-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 10 编码为： 100011-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 13 编码为： 100111-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 23 编码为： 10111-16 18:54:45.224 21473-21473/com.example.admin.myapplication I/System.out: 50 编码为： 11

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