Introduction to Degenerate Binary Tree

Last Updated : 30 Nov, 2023

Every non-leaf node has just one child in a binary tree known as a Degenerate Binary tree. The tree effectively transforms into a linked list as a result, with each node linking to its single child.

When a straightforward and effective data structure is required, degenerate binary trees, a special case of binary trees, may be employed. For instance, a degenerate binary tree can be used to create a stack data structure since each node simply needs to store a reference to the next node.
Degenerate binary trees are less effective than balanced binary trees at searching, inserting, and deleting data, though. This is due to the fact that degenerate binary trees may become unbalanced, resulting in performance that is comparable to a linked list in the worst case.
Degenerate binary trees are rarely employed by themselves as a data structure in general. Rather, they are frequently utilized as a component of other data structures like linked lists, stacks, and queues. Degenerate binary trees can also be utilized as a particular instance to take into account in algorithms that traverse or search over binary trees.

Degenerate Binary tree is of two types:

Left-skewed Tree: If all the nodes in the degenerate tree have only a left child.
Right-skewed Tree: If all the nodes in the degenerate tree have only a right child.

Examples:

Input: 1, 2, 3, 4, 5
Output:

Representation of right skewed tree
Explanation: Each parent node in this tree only has one child node. In essence, the tree is a linear chain of nodes.

Approach: To solve the problem follow the below idea:

Idea is to use handle degenerate binary trees relies on the issue at hand. Degenerate trees may typically be transformed into linked lists or arrays, which can make some operations easier.

Steps involved in the implementation of code:

Initializing structure of Tree.
Inserting all data on the right side of a current node.
Printing node by considering only the right node of each node.

Below is the implementation of the Right-skewed Tree:

C++

// C++ implementation of above approach #include <iostream> using namespace std;  class Node { public:     int data;     Node* left;     Node* right;      Node(int val)     {         data = val;         left = NULL;         right = NULL;     } };  // Function to insert nodes on the right side of // current node Node* insert(Node* root, int data) {     if (root == NULL) {         root = new Node(data);     }     else {         root->right = insert(root->right, data);     }     return root; }  // Function to print tree void printTree(Node* node) {     if (node != NULL) {         cout << node->data << endl;         printTree(node->right);     } }  // Driver code int main() {     Node* root = NULL;     root = insert(root, 1);     insert(root, 2);     insert(root, 3);     insert(root, 4);     insert(root, 5);      // Function call     printTree(root);      return 0; }  // This code is contributed by Prajwal Kandekar

Java

class Node {     int data;     Node left;     Node right;      Node(int val)     {         data = val;         left = null;         right = null;     } }  public class Main {     // Function to insert nodes on the right side of     // current node     public static Node insert(Node root, int data)     {         if (root == null) {             root = new Node(data);         }         else {             root.right = insert(root.right, data);         }         return root;     }      // Function to print tree     public static void printTree(Node node)     {         if (node != null) {             System.out.println(node.data);             printTree(node.right);         }     }      // Driver code     public static void main(String[] args)     {         Node root = null;         root = insert(root, 1);         insert(root, 2);         insert(root, 3);         insert(root, 4);         insert(root, 5);          // Function call         printTree(root);     } }

Python3

# Python implementation of above approach class Node:     def __init__(self, data):         self.left = None         self.right = None         self.data = data  # Function to insert nodes on the right side of # current node   def insert(root, data):     if root is None:         root = Node(data)     else:         root.right = insert(root.right, data)     return root  # Function to print tree   def printTree(node):     if node is not None:         print(node.data)         printTree(node.right)   # Driver code root = None root = insert(root, 1) insert(root, 2) insert(root, 3) insert(root, 4) insert(root, 5)  # Function call printTree(root)

// C# implementation of above approach using System;  class Node {     public int data;     public Node left;     public Node right;      public Node(int val)     {         data = val;         left = null;         right = null;     } }  // Function to insert nodes on the right side of // current node class Program {     static Node Insert(Node root, int data)     {         if (root == null) {             root = new Node(data);         }         else {             root.right = Insert(root.right, data);         }         return root;     }     // Function to print tree     static void PrintTree(Node node)     {         if (node != null) {             Console.WriteLine(node.data);             PrintTree(node.right);         }     }     // Driver code     static void Main(string[] args)     {         Node root = null;         root = Insert(root, 1);         Insert(root, 2);         Insert(root, 3);         Insert(root, 4);         Insert(root, 5);          // Function call         PrintTree(root);          Console.ReadKey();     } }

JavaScript

class Node {   constructor(val) {     this.data = val;     this.left = null;     this.right = null;   } }  // Function to insert nodes on the right side of // current node function insert(root, data) {   if (root === null) {     root = new Node(data);   } else {     root.right = insert(root.right, data);   }   return root; }  // Function to print tree function printTree(node) {   if (node !== null) {     console.log(node.data);     printTree(node.right);   } }  // Driver code let root = null; root = insert(root, 1); insert(root, 2); insert(root, 3); insert(root, 4); insert(root, 5);  // Function call printTree(root);

Output

1 2 3 4 5

Output :

Below is the implementation of the Left-skewed Tree:

C++14

// C++ implementation of above approach #include <iostream>  // Node class class Node { public:     int data;     Node* left;     Node* right;      Node(int data) {         this->data = data;         this->left = nullptr;         this->right = nullptr;     } };  // Function to insert nodes on the left side of  // current node Node* insert(Node* root, int data) {     if (root == nullptr) {         root = new Node(data);     }     else {         root->left = insert(root->left, data);     }     return root; }  // Function to print tree void printTree(Node* node) {     if (node != nullptr) {         std::cout << node->data << std::endl;         printTree(node->left);     } }  int main() {     Node* root = nullptr;     root = insert(root, 1);     insert(root, 2);     insert(root, 3);     insert(root, 4);     insert(root, 5);      // Function call     printTree(root);      return 0; }  // This code is contributed by Vaibhav nandan

Java

// Node class class Node {     int data;     Node left;     Node right;      // Constructor to initialize a new node     Node(int data) {         this.data = data;         this.left = null;         this.right = null;     } }  public class BinaryTree {     // Function to insert nodes on the left side of the current node     static Node insert(Node root, int data) {         // If the root is null, create a new node with the given data         if (root == null) {             root = new Node(data);         } else {             // If the root is not null, recursively insert on the left side             root.left = insert(root.left, data);         }         return root;     }      // Function to print the tree using inorder traversal     static void printTree(Node node) {         // Base case: if the node is not null         if (node != null) {             // Print the data of the current node             System.out.println(node.data);             // Recursively print the left subtree             printTree(node.left);         }     }      // Main method     public static void main(String[] args) {         // Create a root node         Node root = null;          // Insert nodes into the tree         root = insert(root, 1);         insert(root, 2);         insert(root, 3);         insert(root, 4);         insert(root, 5);          // Function call to print the tree         printTree(root);     } }

Python3

# Python implementation of above approach class Node:     def __init__(self, data):         self.left = None         self.right = None         self.data = data  # Function to insert nodes on the left side of # current node   def insert(root, data):     if root is None:         root = Node(data)     else:         root.left = insert(root.left, data)     return root  # Function to print tree   def printTree(node):     if node is not None:         print(node.data)         printTree(node.left)   # Driver code root = None root = insert(root, 1) insert(root, 2) insert(root, 3) insert(root, 4) insert(root, 5)  # Function call printTree(root)

using System;  // Node class class Node {     public int Data;     public Node Left;     public Node Right;      public Node(int data)     {         this.Data = data;         this.Left = null;         this.Right = null;     } }  class BinaryTree {     // Function to insert nodes on the left side of the current node     static Node Insert(Node root, int data)     {         if (root == null)         {             root = new Node(data);         }         else         {             root.Left = Insert(root.Left, data);         }         return root;     }      // Function to print the tree (pre-order traversal)     static void PrintTree(Node node)     {         if (node != null)         {             Console.WriteLine(node.Data);             PrintTree(node.Left);         }     }      static void Main()     {         Node root = null;         root = Insert(root, 1);         Insert(root, 2);         Insert(root, 3);         Insert(root, 4);         Insert(root, 5);          // Function call to print the tree         PrintTree(root);     } }

JavaScript

class Node {     constructor(data) {         this.data = data;         this.left = null;         this.right = null;     } }  // Function to insert nodes on the left side of the current node function insert(root, data) {     if (root === null) {         root = new Node(data);     } else {         root.left = insert(root.left, data);     }     return root; }  // Function to print the tree in-order function printTree(node) {     if (node !== null) {         console.log(node.data);         printTree(node.left);     } }  // Main function function main() {     let root = null;     root = insert(root, 1);     root = insert(root, 2);     root = insert(root, 3);     root = insert(root, 4);     root = insert(root, 5);      // Function call to print the tree     printTree(root); }  // Run the main function main();