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📜  数据结构示例-在二叉树中搜索节点

📅  最后修改于: 2020-10-15 06:40:52             🧑  作者: Mango

问：程序搜索二叉树中的节点。

树是非线性数据结构，用于分层存储数据。树是称为节点的元素的集合。节点通过边连接并包含数据。树的第一个节点称为根。每个节点可能有或没有子节点。没有任何子节点的节点称为叶子。

二叉树是另一种树数据结构，其中每个节点最多可以有两个孩子。也就是说，二叉树中的每个节点都会有数据，即左子节点和右子节点。

上图表示二叉树，其中1表示树的根节点。节点2的左子节点为4，节点3的左子节点为5，右子节点为6。节点4,5和6是叶节点，因为它们没有任何子节点。

说明

在此程序中，我们将在二叉树中搜索特定值。如果存在，则print消息“二叉树中存在元素”，否则print消息“二叉树中不存在元素”。简而言之，我们首先将根的数据与要搜索的节点的数据进行比较。如果找到匹配项，则将标志设置为true。否则，在左子树中搜索节点，然后在右子树中搜索。

算法

  • 定义具有三个属性的Node类，即： left和right数据。在此，左代表节点的左子节点，右代表节点的右子节点。
  • 创建节点时，数据将传递到该节点的data属性，并且left和right都将设置为null 。
  • 定义另一个具有两个属性root和flag的类。
    1. 根表示树的根节点，并将其初始化为null。
    2. 该标志将用于检查树中是否存在给定的节点。最初，它将设置为false。
  • searchNode()将在二叉树中搜索特定节点：
    1. 它检查根是否为null ，这表示树为空。
    2. 如果树不为空，它将把温度数据与值进行比较。如果它们相等，则将标志设置为true并返回。
    3. 通过递归调用searchNode()遍历左子树，并检查左子树中是否存在该值。
    4. 通过递归调用searchNode()遍历右子树，并检查右子树中是否存在该值。

示例：

Python

#Represent a node of binary tree
class Node:
    def __init__(self,data):
        #Assign data to the new node, set left and right children to None
        self.data = data;
        self.left = None;
        self.right = None;
 
class SearchBinaryTree:
    def __init__(self):
        #Represent the root of binary tree
        self.root = None;
        self.flag = False;
    
    #searchNode() will search for the particular node in the binary tree
    def searchNode(self, temp, value):
        #Check whether tree is empty
        if(self.root == None):
            print("Tree is empty");
        
        else:
            #If value is found in the given binary tree then, set the flag to true
            if(temp.data == value):
                self.flag = True;
                return;
            
            #Search in left subtree
            if(self.flag == False and temp.left != None):
                self.searchNode(temp.left, value);
            
            #Search in right subtree
            if(self.flag == False and temp.right != None):
                self.searchNode(temp.right, value);
 
bt = SearchBinaryTree();
#Add nodes to the binary tree
bt.root = Node(1);
bt.root.left = Node(2);
bt.root.right = Node(3);
bt.root.left.left = Node(4);
bt.root.right.left = Node(5);
bt.root.right.right = Node(6);
        
#Search for node 5 in the binary tree
bt.searchNode(bt.root, 5);
 
if(bt.flag):
    print("Element is present in the binary tree");
else:
    print("Element is not present in the binary tree");

输出：

Element is present in the binary tree

C

#include 
#include 
#include 
 
//Represent a node of binary tree
struct node{
    int data;
    struct node *left;
    struct node *right;
};
 
//Represent the root of binary tree
struct node *root = NULL;
 
static bool flag = false;
 
//createNode() will create a new node
struct node* createNode(int data){
    //Create a new node
    struct node *newNode = (struct node*)malloc(sizeof(struct node));
    //Assign data to newNode, set left and right children to NULL
    newNode->data = data;
    newNode->left = NULL;
    newNode->right = NULL;
    
    return newNode;
}
 
//searchNode() will search for the particular node in the binary tree
void searchNode(struct node *temp, int value){
    //Check whether tree is empty
    if(root == NULL){
        printf("Tree is empty\n");
    }
    else{
        //If value is found in the given binary tree then, set the flag to true
        if(temp->data == value){
            flag = true;
             return;
        }
        //Search in left subtree
        if(flag == false && temp->left != NULL){
        searchNode(temp->left, value);
        }
        //Search in right subtree
        if(flag == false && temp->right != NULL){
        searchNode(temp->right, value);
        }
    }
}
 
int main()
{
    //Add nodes to the binary tree
    root = createNode(1);
    root->left = createNode(2);
    root->right = createNode(3);
    root->left->left = createNode(4);
    root->right->left = createNode(5);
    root->right->right = createNode(6);
        
    //Search for node 5 in the binary tree
    searchNode(root, 5);
    
    if(flag)
        printf("Element is present in the binary tree");
    else
        printf("Element is not present in the binary tree");
    return 0;
}

输出：

Element is present in the binary tree

JAVA

public class SearchBinaryTree {
      
      //Represent a node of binary tree
      public static class Node{
        int data;
        Node left;
        Node right;
        
        public Node(int data){
          //Assign data to the new node, set left and right children to null
          this.data = data;
          this.left = null;
          this.right = null;
        }
      }
      
      //Represent the root of binary tree
      public Node root;
      
      public static boolean flag = false;
      
      public SearchBinaryTree(){
        root = null;
      }
      
      //searchNode() will search for the particular node in the binary tree
      public void searchNode(Node temp, int value){
        //Check whether tree is empty
        if(root == null){
          System.out.println("Tree is empty");
        }
        else{
          //If value is found in the given binary tree then, set the flag to true
          if(temp.data == value){
            flag = true;
               return;
          }
          //Search in left subtree
          if(flag == false && temp.left != null){
             searchNode(temp.left, value);
          }
          //Search in right subtree
          if(flag == false && temp.right != null){
             searchNode(temp.right, value);
          }
        }
      }
      
      public static void main(String[] args) {
       
        SearchBinaryTree bt = new SearchBinaryTree();
        //Add nodes to the binary tree
        bt.root = new Node(1);
        bt.root.left = new Node(2);
        bt.root.right = new Node(3);
        bt.root.left.left = new Node(4);
        bt.root.right.left = new Node(5);
        bt.root.right.right = new Node(6);
        
        //Search for node 5 in the binary tree
           bt.searchNode(bt.root, 5);
        
        if(flag)
          System.out.println("Element is present in the binary tree");
        else
          System.out.println("Element is not present in the binary tree");        
      }
    }

输出：

Element is present in the binary tree

C＃

using System; 
namespace Tree 
{                     
    public class Program
    {
        //Represent a node of binary tree
        public class Node{
            public T data;
            public Node left;
            public Node right;
            
            public Node(T data) {
                //Assign data to the new node, set left and right children to null
                this.data = data;
                this.left = null;
                this.right = null;
            }
        }
        
        public class SearchBinaryTree{
            //Represent the root of binary tree
            public Node root;
 
            public static Boolean flag = false;
 
            public SearchBinaryTree(){
                root = null;
            }
        
            //searchNode() will search for the particular node in the binary tree
            public void searchNode(Node temp, T value){
                //Check whether tree is empty
                if(root == null){
                  Console.WriteLine("Tree is empty");
                }
                else{
                    //If value is found in the given binary tree then, set the flag to true
                    if(temp.data.Equals(value)){
                        flag = true;
                        return;
                    }
                    //Search in left subtree
                    if(flag == false && temp.left != null){
                        searchNode(temp.left, value);
                    }
                    //Search in right subtree
                    if(flag == false && temp.right != null){
                         searchNode(temp.right, value);
                    }
                }
            }
        }
        
        public static void Main()
        {
            SearchBinaryTree bt = new SearchBinaryTree();
            //Add nodes to the binary tree
            bt.root = new Node(1);
            bt.root.left = new Node(2);
            bt.root.right = new Node(3);
            bt.root.left.left = new Node(4);
            bt.root.right.left = new Node(5);
            bt.root.right.right = new Node(6);
 
            //Search for node 5 in the binary tree
            bt.searchNode(bt.root, 5);
 
            if(SearchBinaryTree.flag)
              Console.WriteLine("Element is present in the binary tree");
            else
              Console.WriteLine("Element is not present in the binary tree");
        }    
    }
}

输出：

Element is present in the binary tree

PHP：




data = $data;
        $this->left = NULL;
        $this->right = NULL;
    }
}
class SearchBinaryTree{
    //Represent the root of binary tree
    public $root;
    public $flag;
    function __construct(){
        $this->root = NULL;
        $this->flag = false;
    }
    
    //searchNode() will search for the particular node in the binary tree
    function searchNode($temp, $value){
        //Check whether tree is empty
        if($this->root == NULL){
          echo "Tree is empty
";
        }
        else{
          //If value is found in the given binary tree then, set the flag to true
          if($temp->data == $value){
              $this->flag = true;
              return;
          }
          //Search in left subtree
          if($this->flag == false && $temp->left != NULL){
              $this->searchNode($temp->left, $value);
          }
          //Search in right subtree
          if($this->flag == false && $temp->right != NULL){
              $this->searchNode($temp->right, $value);
          }
        }
    }
}
$bt = new SearchBinaryTree();
//Add nodes to the binary tree
$bt->root = new Node(1);
$bt->root->left = new Node(2);
$bt->root->right = new Node(3);
$bt->root->left->left = new Node(4);
$bt->root->right->left = new Node(5);
$bt->root->right->right = new Node(6);
 
//Search for node 5 in the binary tree
$bt->searchNode($bt->root, 5);
 
if($bt->flag)
    echo "Element is present in the binary tree";
else
    echo "Element is not present in the binary tree";      
?>

输出：

Element is present in the binary tree