Java中二叉树数据结构的实现示例

 import java.util.Scanner;      public class BinaryTree {     public static String[] str;     public static int count;        /**      * 静态内部类，定义二叉树节点      */     static class TreeNode {       public String data;       TreeNode lchild;       TreeNode rchild;          public TreeNode(String x) {         this.data = x;       }     }        /**      * 根据前序序列递归构建二叉树      *      * @return      */     public static TreeNode createBtree() {       TreeNode root = null;          if (count >= str.length || str[count++].equals("#")) {         root = null;       } else {         root = new TreeNode(str[count - 1]);         root.lchild = createBtree();         root.rchild = createBtree();       }          return root;     }        /**      * 前序遍历      *      * @param root      */     public static void preTraverse(TreeNode root) {       if (root != null) {         System.out.print(root.data + " ");         preTraverse(root.lchild);         preTraverse(root.rchild);       }     }        /**      * 中序遍历      *      * @param root      */     public static void inTraverse(TreeNode root) {       if (root != null) {         inTraverse(root.lchild);         System.out.print(root.data + " ");         inTraverse(root.rchild);       }     }        /**      * 后序遍历      *      * @param root      */     public static void postTraverse(TreeNode root) {       if (root != null) {         postTraverse(root.lchild);         postTraverse(root.rchild);         System.out.print(root.data + " ");       }     }        public static void main(String args[]) {       Scanner cin = new Scanner(System.in);          while (cin.hasNext()) {         String s = cin.nextLine();         str = s.split(",");            count = 0;            TreeNode root = createBtree();            // 前序遍历         preTraverse(root);         System.out.println();            // 中序遍历         inTraverse(root);         System.out.println();            // 后序遍历         postTraverse(root);         System.out.println();       }     }   }

class Node{ String name; Node left; Node right; public Node(String name) { this.name = name; } @Override public String toString() { return name; }}//定义二叉树class BinaryTree{ Node root;  public BinaryTree(){ root = null; } //为了方便起见，我就直接写个初始化的二叉树，详细的可以见以前的日志 public void initTree(){  Node node1 = new Node("a"); Node node2 = new Node("b"); Node node3 = new Node("c"); Node node4 = new Node("d"); Node node5 = new Node("e"); root = node1; node1.left = node2; node2.right = node3; node1.right = node4; node3.left = node5; } //求二叉树的深度 int length(Node root){ int depth1; int depth2; if(root == null) return 0; //左子树的深度 depth1 = length(root.right); //右子树的深度 depth2 = length(root.left); if(depth1>depth2)  return depth1+1; else  return depth2+1; }}public class TestMatch{ public static void main(String[] args) { BinaryTree tree = new BinaryTree(); tree.initTree(); System.out.println(tree.length(tree.root)); }}