Java实现二叉树的基本操作

[java]
package D0726; 
 
import java.util.ArrayDeque; 
import java.util.Queue; 
 
public class TestTree { 
    public static void main(String[] args) { 
        // 测试Treenode 
        Treenode node = buildTree(null, 1); 
        System.out.print("先序遍历："); 
        preOrder(node); 
        System.out.println(); 
        System.out.print("中序遍历："); 
        inOrder(node); 
        System.out.println(); 
        System.out.print("后序遍历："); 
        postOrder(node); 
        System.out.println(); 
        System.out.print("层次遍历："); 
        levelOrder(node); 
        System.out.println(); 
        System.out.print("叶子节点数目："); 
        System.out.println(leafNum(node)); 
        System.out.print("二叉树的深度："); 
        System.out.println(deep(node)); 
         
    } 
 
    // 建立树@k用来控制树的深度 
    static char i = 'a';// 节点 
 
    public static Treenode buildTree(Treenode node, int k) { 
        if (k > 4) 
            return null; 
        if (node == null) { 
            node = new Treenode(" " + i++); 
        } 
        node.lChild = buildTree(node.lChild, k + 1); 
        node.rChild = buildTree(node.rChild, k + 1); 
        return node; 
    } 
 
    // 根据先序和中序来构建二叉树 
    public Treenode buildTree(String pre, String in) { 
        if (pre.length() <= 0) 
            return null; 
        Treenode root = new Treenode(pre.charAt(0) + ""); 
        // 以根节点为中心，将中序分为两个子序列 
        String leftin = ""; 
        String rightin = ""; 
 
        // 根所左中序的长度，将先序分为左右两个子先序 
        String leftpre = ""; 
        String rightpre = ""; 
        root.lChild = buildTree(leftpre, leftin); 
        root.rChild = buildTree(rightpre, rightin); 
        return root; 
    } 
 
    // 先序遍历 
    public static void preOrder(Treenode node) { 
        if (node != null) { 
            System.out.print(node.data); 
            preOrder(node.lChild); 
            preOrder(node.rChild); 
        } 
    } 
 
    // 中序遍历 
    public static void inOrder(Treenode node) { 
        if (node != null) { 
            inOrder(node.lChild); 
            System.out.print(node.data); 
            inOrder(node.rChild); 
        } 
    } 
 
    // 后序遍历 
    public static void postOrder(Treenode node) { 
        if (node != null) { 
            postOrder(node.lChild); 
            postOrder(node.rChild); 
            System.out.print(node.data); 
        } 
    } 
 
    // 层次遍历 
    public static void levelOrder(Treenode node) { 
        if (node == null) 
            return; 
        Queue<Treenode> queue = new ArrayDeque<Treenode>(); 
        queue.add(node); 
        while (!queue.isEmpty()) { 
            Treenode temp = queue.poll(); 
            System.out.print(temp.data); 
            if (temp.lChild != null) 
                queue.add(temp.lChild); 
            if (temp.rChild != null) 
                queue.add(temp.rChild); 
        } 
    } 
 
    // 求树的叶子节点数 
    public static int leafNum(Treenode node) { 
        if (node != null) { 
            if (node.lChild == null && node.rChild == null) { 
                return 1; 
            } 
            return leafNum(node.lChild)+leafNum(node.rChild); 
        }

补充：软件开发 , Java ,