二叉树的遍历分为递归遍历和非递归遍历
一、递归实现前、中、后序遍历
Node.java:
public class Node { private Object data; Node richild; Node lechild; public Object getData() { return data; } public void setData(Object data) { this.data = data; } public Node getRichild() { return richild; } public void setRichild(Node richild) { this.richild = richild; } public Node getLechild() { return lechild; } public void setLechild(Node lechild) { this.lechild = lechild; } public Node(Object data, Node lechild, Node richild) { super(); this.data = data; this.richild = richild; this.lechild = lechild; } public Node() { super(); } }
递归遍历:
public class BTree { private static Node root; //构造树 public static void init() { Node node1 = new Node("A", null, null); Node node2 = new Node("B", node1, null); Node node3 = new Node("C", null, null); Node node4 = new Node("D", node2, node3); Node node5 = new Node("E", null, null); Node node6 = new Node("F", null, node5); Node node7 = new Node("G", node4, node6); root = node7; } //访问节点 public static void visited(Node n) { System.out.print(n.getData() + " "); } //前序遍历 public static void preOrder(Node n) { if (n != null) { visited(n); preOrder(n.getLechild()); preOrder(n.getRichild()); } } //中序遍历 public static void inOrder(Node n) { if (n != null) { inOrder(n.getLechild()); visited(n); inOrder(n.getRichild()); } } //后序遍历 public static void postOrder(Node n) { if (n != null) { postOrder(n.getLechild()); postOrder(n.getRichild()); visited(n); } } public static void main(String[] args) { init(); System.out.print("递归前序:"); preOrder(root); System.out.println(); System.out.print("递归中序:"); inOrder(root); System.out.println(); System.out.print("递归后序:"); postOrder(root); System.out.println(); } }
二、非递归实现前、中、后序遍历
import java.util.Stack; public class BTree2 { private static Node root; //构造树 public static void init() { Node node1 = new Node("A", null, null); Node node2 = new Node("B", node1, null); Node node3 = new Node("C", null, null); Node node4 = new Node("D", node2, node3); Node node5 = new Node("E", null, null); Node node6 = new Node("F", null, node5); Node node7 = new Node("G", node4, node6); root = node7; } //前序遍历 public static void preOrder(Node n) { System.out.print("非递归前序:"); Stack<Node> stack = new Stack<>(); int index = 0; while (n != null || index > 0) { while (n != null) { System.out.print(n.getData() + " "); stack.push(n); index++; n = n.getLechild(); } n = stack.pop(); index--; n = n.getRichild(); } } //中序遍历 public static void inOrder(Node n) { System.out.print("非递归中序:"); Stack<Node> stack = new Stack<>(); int index = 0; while (n != null || index > 0) { while (n != null) { stack.push(n); index++; n = n.getLechild(); } n = stack.pop(); System.out.print(n.getData() + " "); index--; n = n.getRichild(); } } //后序遍历 public static void postOrder(Node n) { System.out.print("非递归后序:"); Stack<Node> stack = new Stack<>(); int index = 0; Node lastVisited = null; while (n != null || index > 0) { while (n != null) { stack.push(n); index++; n = n.getLechild(); } n = stack.peek(); if (n.getRichild() == null || n.getRichild() == lastVisited) { System.out.print(n.getData() + " "); lastVisited = n; index--; stack.pop(); n = null; } else { n = n.getRichild(); } } } public static void main(String[] args) { init(); preOrder(root); System.out.println(); inOrder(root); System.out.println(); postOrder(root); System.out.println(); } }
三、查找最大值
// 查找最大值 public static Node maxNode() { Node node = root; Node maxNode = node; while (node != null) { maxNode = node; node = node.getRichild(); } return maxNode; }
四、查找最小值
// 查找最小值 public static Node minNode() { Node node = root; Node minNode = node; while (node != null) { minNode = node; node = node.getLechild(); } return minNode; }
五、插入节点
// 插入节点 public static boolean insert(Object data, Node parent) { Node node = new Node(data, null, null); if (root == null || parent == null) { root = node; return true; } else if (parent.getLechild() != null && parent.getRichild() != null) { return false; } else { if (parent.getLechild() != null) { parent.setRichild(node); } else { parent.setLechild(node); } return true; } }
六、查找节点
// 查找节点 public static void find(Node n, Object data) { if (n != null) { if (n.getData() == data) { System.out.println(n); return; } else { find(n.getLechild(), data); find(n.getRichild(), data); } } }
原文地址:https://www.cnblogs.com/ericz2j/p/10679324.html
时间: 2024-10-15 06:26:32