网站基本配置,中国公司排行榜前十名,360网页入口,自建网站做跨境电商一、二叉树的定义 //定义一个二叉树#xff1a;使用链式存储
public class TreeNode {int val; // 节点的值TreeNode left; // 左子节点TreeNode right; // 右子节点public TreeNode() {}// 构造函数#xff0c;初始化节点值public TreeNode(int val){this.valval;}// 构造函…一、二叉树的定义 //定义一个二叉树使用链式存储
public class TreeNode {int val; // 节点的值TreeNode left; // 左子节点TreeNode right; // 右子节点public TreeNode() {}// 构造函数初始化节点值public TreeNode(int val){this.valval;}// 构造函数初始化节点值、左子节点和右子节点public TreeNode(int val, TreeNode left, TreeNode right) {this.val val;this.left left;this.right right;}}二、前序遍历
package com.thirteenday.tree;import java.util.ArrayList;
import java.util.List;//前序遍历
/*** 递归三部曲* 1、确定递归函数的参数和返回值* 2、确定递归终止条件* 3、确定单层递归的逻辑*/
public class PreorderTraversal {/*** 1、确定递归函数的参数和返回值* param root 树的根节点* param result 将遍历的结果放在集合中*/private static void preorder(TreeNode root , ListInteger result){//2、确定递归终止条件if (root null){return;}//3、确定单层递归的逻辑前序遍历根左右result.add(root.val); //根preorder(root.left,result);//左preorder(root.right,result); //右}public static ListInteger preorderTraversal(TreeNode root){ArrayListInteger result new ArrayList();preorder(root,result);return result;}public static void main(String[] args) {TreeNode root new TreeNode(1, new TreeNode(2, new TreeNode(4), new TreeNode(5)), new TreeNode(3, new TreeNode(6), new TreeNode(7)));ListInteger list preorderTraversal(root);list.stream().forEach( e - System.out.println(e ));}}
三、中序遍历
package com.thirteenday.tree;import java.util.ArrayList;
import java.util.List;//中序遍历
public class InorderTraversal {/*** 1、确定递归函数的参数和返回值* param root 树的根节点* param result 将遍历的结果放在集合中*/private static void preorder(TreeNode root , ListInteger result){//2、确定递归终止条件if (root null){return;}//3、确定单层递归的逻辑中序遍历左根右preorder(root.left,result);//左result.add(root.val); //根preorder(root.right,result); //右}public static ListInteger inorderTraversal(TreeNode root){ArrayListInteger result new ArrayList();preorder(root,result);return result;}public static void main(String[] args) {TreeNode root new TreeNode(1, new TreeNode(2, new TreeNode(4), new TreeNode(5)), new TreeNode(3, new TreeNode(6), new TreeNode(7)));ListInteger list inorderTraversal(root);list.stream().forEach( e - System.out.println(e ));}
}
四、后序遍历
//后序遍历
public class PostorderTraversal {/*** 1、确定递归函数的参数和返回值* param root 树的根节点* param result 将遍历的结果放在集合中*/private static void preorder(TreeNode root , ListInteger result){//2、确定递归终止条件if (root null){return;}//3、确定单层递归的逻辑后序遍历左右根preorder(root.left,result);//左preorder(root.right,result); //右result.add(root.val); //根}public static ListInteger postorderTraversal(TreeNode root){ArrayListInteger result new ArrayList();preorder(root,result);return result;}public static void main(String[] args) {TreeNode root new TreeNode(1, new TreeNode(2, new TreeNode(4), new TreeNode(5)), new TreeNode(3, new TreeNode(6), new TreeNode(7)));ListInteger list postorderTraversal(root);list.stream().forEach( e - System.out.println(e ));}
}
