Java_二叉树用途

赫夫曼树

• 赫夫曼树的构造

• 赫夫曼树构造过程

赫夫曼编码 Paste_Image.png

查找二叉树

/**
 * 查找二叉树
 * @author Administrator
 *
 */
public class SearchBinaryTree {
    //根结点
    public TreeNode root;

    public class TreeNode {
        public int index;
        public int data;
        public TreeNode leftChild;
        public TreeNode rightChild;
        public TreeNode parent;// 父节点

        public TreeNode(int index, int data) {
            this.data = data;
        }
    }

    /**
     * 二叉树左边孩子都比根结点小，右边孩子都比根结点大
     * 
     * @param dataList
     */
    public TreeNode buildSearchTree(int index, int data) {
        TreeNode node = null;
        TreeNode parentNode = null;
        if (root == null) {
            node = new TreeNode(index, data);
            root = node;
        }

        node = root;
        // 查找合适的位置
        while (node != null) {
            parentNode = node;
            if (node.data > data) {
                node = node.leftChild;
            } else if (node.data < data) {
                node = node.rightChild;
            } else {
                return node;
            }
        }
        //退出while循环时，node为null需要创建
        node = new TreeNode(index, data);
        if (parentNode.data > data) {
            parentNode.leftChild = node;
        } else if (parentNode.data < data) {
            parentNode.rightChild = node;
        }
        node.parent = parentNode;
        return node;
    }

    /**
     * 中序遍历二叉树
     * @param node
     */
    public void print(TreeNode node) {
        if (node == null) {
            return;
        }
        print(node.leftChild);
        System.out.print("　"+node.data);
        print(node.rightChild);
        
    }

    public static void main(String[] args) {
        SearchBinaryTree binaryTree = new SearchBinaryTree();
        int[] array = { 3, 2, 6, 12, 5, 1, 28, 20, 30, 15 };
        for (int i = 0; i < array.length; i++) {
            binaryTree.buildSearchTree(i, array[i]);
        }
        
        binaryTree.print(binaryTree.root);
    }

}