java遍歷二叉樹：前序遍歷，中序遍歷，後序遍歷，遍歷深度，求葉子節點個數，層次遍歷
阿新 • • 發佈：2018-12-10
import java.util.ArrayDeque; import java.util.Queue; public class CreateTree { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Node root = new Node(); root.data = 9; Node temp01 = new Node(); temp01.data = 1; root.left = temp01; Node temp02 = new Node(); temp02.data = 3; root.right = temp02; Node temp03 = new Node(); temp03.data = 2; root.left.left = temp03; Node temp04 = new Node(); temp04.data = 4; root.left.right = temp04; Node temp05 = new Node(); temp05.data = 8; root.right.left = temp05; Node temp06 = new Node(); temp06.data = 6; root.left.left.left = temp06; Node temp07 = new Node(); temp07.data = 7; root.left.left.right = temp07; System.out.println("--------先序遍歷----------"); SelectTree1(root); System.out.println(); System.out.println("---------中序遍歷---------"); SelectTree(root); System.out.println(); System.out.println("---------後序遍歷---------"); SelectTree2(root); System.out.println(); System.out.println("----------葉節點個數-----------"); int i = leafNum(root); System.out.println(i); System.out.println("----------層次遍歷二叉樹-----------------"); levelOrder(root); System.out.println(); int j = deep(root); System.out.println("---------高度---------"); System.out.println(j); } // 中序遍歷 public static void SelectTree(Node root) { if (root == null) return; SelectTree(root.left); System.out.print(root.data + " "); SelectTree(root.right); } // 先序遍歷 public static void SelectTree1(Node root) { if (root == null) return; System.out.print(root.data + " "); SelectTree1(root.left); SelectTree1(root.right); } // 後序遍歷 public static void SelectTree2(Node root) { if (root == null) return; SelectTree2(root.left); SelectTree2(root.right); System.out.print(root.data + " "); } // 葉子數 public static int leafNum(Node node) { if (node != null) { if (node.left == null && node.right == null) { return 1; } return leafNum(node.left) + leafNum(node.right); } return 0; } // 求二叉樹的深度 public static int deep(Node node) { int h1, h2; if (node == null) { return 0; } else { h1 = deep(node.left); h2 = deep(node.right); return (h1 < h2) ? h2 + 1 : h1 + 1; } } // 層次遍歷 public static void levelOrder(Node node) { if (node == null) return; Queue<Node> queue = new ArrayDeque<Node>(); queue.add(node); while (!queue.isEmpty()) { Node temp = queue.poll(); System.out.print(temp.data); if (temp.left != null) queue.add(temp.left); if (temp.right != null) queue.add(temp.right); } } } class Node { boolean visited = false; int data = 0; Node left = null; Node right = null; }