描述
二叉树的构建、插入新的结点、树的先中后序以及层序四种遍历
代码
import java.util.LinkedList; import java.util.Queue; class Node{ public int data; public Node left; public Node right; public Node(int data){ this.data=data; this.left=null; this.right=null; } } public class BinaryTree { private Node root; public BinaryTree(){ root=null; } /* * 插入到排序二叉树 * */ public void insert(int data){ Node newNode=new Node(data); if(root==null){ root=newNode; return; } Node node=root; Node parent; while(true){ parent=node; if(data<node.data){ node=node.left; if(node==null){ parent.left=newNode; return; } }else{ node=node.right; if(node==null){ parent.right=newNode; return; } } } } /* * 将数值输入构建二叉树 * */ public void buildTree(int[] data){ for(int i=0;i<data.length;i++){ insert(data[i]); } } /* * 先序遍历 * */ public void preOrder(){ preOrder(root); } public void preOrder(Node node){ if(node==null) return; System.out.print(node.data+" "); preOrder(node.left); preOrder(node.right); } /* * 中序遍历 * */ public void inOrder(){ inOrder(root); } public void inOrder(Node node){ if(node==null) return; inOrder(node.left); System.out.print(node.data+" "); inOrder(node.right); } /* * 后序遍历 * */ public void postOrder(){ postOrder(root); } public void postOrder(Node node){ if(node==null) return; postOrder(node.left); postOrder(node.right); System.out.print(node.data+" "); } /* * 层序遍历 * */ public void layerTranverse(){ Node node = root; Queue<Node> queque=new LinkedList<Node>(); queque.add(root); while(!queque.isEmpty()){ node=queque.poll(); System.out.print(node.data+" "); if(node.left!=null) queque.add(node.left); if(node.right!=null) queque.add(node.right); } } public static void main(String[] args) { BinaryTree bitree=new BinaryTree(); int[] data={2,8,7,4,9,3,1,6,7,5}; bitree.buildTree(data); System.out.print("二叉树的先序遍历:"); bitree.preOrder(); System.out.println(); System.out.print("二叉树的中序遍历:"); bitree.inOrder(); System.out.println(); System.out.print("二叉树的后序遍历:"); bitree.postOrder(); System.out.println(); System.out.print("二叉树的层序遍历:"); bitree.layerTranverse(); System.out.println(); } }