Creating a tree with Left-Child Right-Sibling Representation
Left-Child Right-Sibling Representation is a different representation of an n-ary tree where instead of holding a reference to each and every child node, a node holds just two references, first a reference to its first child, and the other to its immediate next sibling. This new transformation not only removes the need for advanced knowledge of the number of children a node has but also limits the number of references to a maximum of two, thereby making it so much easier to code.
At each node, link children of same parent from left to right. Parent should be linked with only first child.
Examples:
Left Child Right Sibling tree representation 10 | 2 -> 3 -> 4 -> 5 | | 6 7 -> 8 -> 9
Prerequisite: Left-Child Right-Sibling Representation of Tree
Below is the implementation.
C++
// C++ program to create a tree with left child // right sibling representation. #include<bits/stdc++.h> using namespace std; struct Node { int data; struct Node *next; struct Node *child; }; // Creating new Node Node* newNode( int data) { Node *newNode = new Node; newNode->next = newNode->child = NULL; newNode->data = data; return newNode; } // Adds a sibling to a list with starting with n Node *addSibling(Node *n, int data) { if (n == NULL) return NULL; while (n->next) n = n->next; return (n->next = newNode(data)); } // Add child Node to a Node Node *addChild(Node * n, int data) { if (n == NULL) return NULL; // Check if child list is not empty. if (n->child) return addSibling(n->child, data); else return (n->child = newNode(data)); } // Traverses tree in depth first order void traverseTree(Node * root) { if (root == NULL) return ; while (root) { cout << " " << root->data; if (root->child) traverseTree(root->child); root = root->next; } } //Driver code int main() { /* Let us create below tree * 10 * / / \ \ * 2 3 4 5 * | / | \ * 6 7 8 9 */ // Left child right sibling /* 10 * | * 2 -> 3 -> 4 -> 5 * | | * 6 7 -> 8 -> 9 */ Node *root = newNode(10); Node *n1 = addChild(root, 2); Node *n2 = addChild(root, 3); Node *n3 = addChild(root, 4); Node *n4 = addChild(n3, 6); Node *n5 = addChild(root, 5); Node *n6 = addChild(n5, 7); Node *n7 = addChild(n5, 8); Node *n8 = addChild(n5, 9); traverseTree(root); return 0; } |
Java
// Java program to create a tree with left child // right sibling representation. class GFG { static class NodeTemp { int data; NodeTemp next, child; public NodeTemp( int data) { this .data = data; next = child = null ; } } // Adds a sibling to a list with starting with n static public NodeTemp addSibling(NodeTemp node, int data) { if (node == null ) return null ; while (node.next != null ) node = node.next; return (node.next = new NodeTemp(data)); } // Add child Node to a Node static public NodeTemp addChild(NodeTemp node, int data) { if (node == null ) return null ; // Check if child is not empty. if (node.child != null ) return (addSibling(node.child,data)); else return (node.child = new NodeTemp(data)); } // Traverses tree in depth first order static public void traverseTree(NodeTemp root) { if (root == null ) return ; while (root != null ) { System.out.print(root.data + " " ); if (root.child != null ) traverseTree(root.child); root = root.next; } } // Driver code public static void main(String args[]) { /* Let us create below tree * 10 * / / \ \ * 2 3 4 5 * | / | \ * 6 7 8 9 */ // Left child right sibling /* 10 * | * 2 -> 3 -> 4 -> 5 * | | * 6 7 -> 8 -> 9 */ NodeTemp root = new NodeTemp( 10 ); NodeTemp n1 = addChild(root, 2 ); NodeTemp n2 = addChild(root, 3 ); NodeTemp n3 = addChild(root, 4 ); NodeTemp n4 = addChild(n3, 6 ); NodeTemp n5 = addChild(root, 5 ); NodeTemp n6 = addChild(n5, 7 ); NodeTemp n7 = addChild(n5, 8 ); NodeTemp n8 = addChild(n5, 9 ); traverseTree(root); } } // This code is contributed by M.V.S.Surya Teja. |
Python3
# Python3 program to create a tree with # left child right sibling representation. # Creating new Node class newNode: def __init__( self , data): self . Next = self .child = None self .data = data # Adds a sibling to a list with # starting with n def addSibling(n, data): if (n = = None ): return None while (n. Next ): n = n. Next n. Next = newNode(data) return n. Next # Add child Node to a Node def addChild(n, data): if (n = = None ): return None # Check if child list is not empty. if (n.child): return addSibling(n.child, data) else : n.child = newNode(data) return n.child # Traverses tree in depth first order def traverseTree(root): if (root = = None ): return while (root): print (root.data, end = " " ) if (root.child): traverseTree(root.child) root = root. Next # Driver code if __name__ = = '__main__' : # Let us create below tree # 10 # / / \ \ # 2 3 4 5 # | / | \ # 6 7 8 9 # Left child right sibling # 10 # | # 2 -> 3 -> 4 -> 5 # | | # 6 7 -> 8 -> 9 root = newNode( 10 ) n1 = addChild(root, 2 ) n2 = addChild(root, 3 ) n3 = addChild(root, 4 ) n4 = addChild(n3, 6 ) n5 = addChild(root, 5 ) n6 = addChild(n5, 7 ) n7 = addChild(n5, 8 ) n8 = addChild(n5, 9 ) traverseTree(root) # This code is contributed by pranchalK |
C#
// C# program to create a tree with left // child right sibling representation. using System; class GFG { public class NodeTemp { public int data; public NodeTemp next, child; public NodeTemp( int data) { this .data = data; next = child = null ; } } // Adds a sibling to a list with // starting with n public static NodeTemp addSibling(NodeTemp node, int data) { if (node == null ) { return null ; } while (node.next != null ) { node = node.next; } return (node.next = new NodeTemp(data)); } // Add child Node to a Node public static NodeTemp addChild(NodeTemp node, int data) { if (node == null ) { return null ; } // Check if child is not empty. if (node.child != null ) { return (addSibling(node.child,data)); } else { return (node.child = new NodeTemp(data)); } } // Traverses tree in depth first order public static void traverseTree(NodeTemp root) { if (root == null ) { return ; } while (root != null ) { Console.Write(root.data + " " ); if (root.child != null ) { traverseTree(root.child); } root = root.next; } } // Driver code public static void Main( string [] args) { /* Let us create below tree * 10 * / / \ \ * 2 3 4 5 * | / | \ * 6 7 8 9 */ // Left child right sibling /* 10 * | * 2 -> 3 -> 4 -> 5 * | | * 6 7 -> 8 -> 9 */ NodeTemp root = new NodeTemp(10); NodeTemp n1 = addChild(root, 2); NodeTemp n2 = addChild(root, 3); NodeTemp n3 = addChild(root, 4); NodeTemp n4 = addChild(n3, 6); NodeTemp n5 = addChild(root, 5); NodeTemp n6 = addChild(n5, 7); NodeTemp n7 = addChild(n5, 8); NodeTemp n8 = addChild(n5, 9); traverseTree(root); } } // This code is contributed by Shrikant13 |
Javascript
<script> // Javascript program to create a tree with left child // right sibling representation. class NodeTemp { constructor(data) { this .data=data; this .next = this .child = null ; } } // Adds a sibling to a list with starting with n function addSibling(node,data) { if (node == null ) return null ; while (node.next != null ) node = node.next; return (node.next = new NodeTemp(data)); } // Add child Node to a Node function addChild(node,data) { if (node == null ) return null ; // Check if child is not empty. if (node.child != null ) return (addSibling(node.child,data)); else return (node.child = new NodeTemp(data)); } // Traverses tree in depth first order function traverseTree(root) { if (root == null ) return ; while (root != null ) { document.write(root.data + " " ); if (root.child != null ) traverseTree(root.child); root = root.next; } } // Driver code /* Let us create below tree * 10 * / / \ \ * 2 3 4 5 * | / | \ * 6 7 8 9 */ // Left child right sibling /* 10 * | * 2 -> 3 -> 4 -> 5 * | | * 6 7 -> 8 -> 9 */ let root = new NodeTemp(10); let n1 = addChild(root,2); let n2 = addChild(root,3); let n3 = addChild(root,4); let n4 = addChild(n3,6); let n5 = addChild(root,5); let n6 = addChild(n5,7); let n7 = addChild(n5,8); let n8 = addChild(n5,9); traverseTree(root); // This code is contributed by patel2127 </script> |
10 2 3 4 6 5 7 8 9
Time Complexity: O(n2), where n is the number of nodes in the tree.
Auxiliary Space: O(n)
Level Order Traversal: The above code talks about depth-first traversal. We can also do level order traversal of such representation.
Implementation:
C++
// C++ program to create a tree with left child // right sibling representation. #include <bits/stdc++.h> using namespace std; struct Node { int data; struct Node* next; struct Node* child; }; // Creating new Node Node* newNode( int data) { Node* newNode = new Node; newNode->next = newNode->child = NULL; newNode->data = data; return newNode; } // Adds a sibling to a list with starting with n Node* addSibling(Node* n, int data) { if (n == NULL) return NULL; while (n->next) n = n->next; return (n->next = newNode(data)); } // Add child Node to a Node Node* addChild(Node* n, int data) { if (n == NULL) return NULL; // Check if child list is not empty. if (n->child) return addSibling(n->child, data); else return (n->child = newNode(data)); } // Traverses tree in level order void traverseTree(Node* root) { // Corner cases if (root == NULL) return ; cout << root->data << " " ; if (root->child == NULL) return ; // Create a queue and enqueue root queue<Node*> q; Node* curr = root->child; q.push(curr); while (!q.empty()) { // Take out an item from the queue curr = q.front(); q.pop(); // Print next level of taken out item and enqueue // next level's children while (curr != NULL) { cout << curr->data << " " ; if (curr->child != NULL) { q.push(curr->child); } curr = curr->next; } } } // Driver code int main() { Node* root = newNode(10); Node* n1 = addChild(root, 2); Node* n2 = addChild(root, 3); Node* n3 = addChild(root, 4); Node* n4 = addChild(n3, 6); Node* n5 = addChild(root, 5); Node* n6 = addChild(n5, 7); Node* n7 = addChild(n5, 8); Node* n8 = addChild(n5, 9); traverseTree(root); return 0; } |
Java
// Java program to create a tree with left child // right sibling representation. import java.util.*; class GFG { static class Node { int data; Node next; Node child; }; // Creating new Node static Node newNode( int data) { Node newNode = new Node(); newNode.next = newNode.child = null ; newNode.data = data; return newNode; } // Adds a sibling to a list with starting with n static Node addSibling(Node n, int data) { if (n == null ) return null ; while (n.next != null ) n = n.next; return (n.next = newNode(data)); } // Add child Node to a Node static Node addChild(Node n, int data) { if (n == null ) return null ; // Check if child list is not empty. if (n.child != null ) return addSibling(n.child, data); else return (n.child = newNode(data)); } // Traverses tree in level order static void traverseTree(Node root) { // Corner cases if (root == null ) return ; System.out.print(root.data+ " " ); if (root.child == null ) return ; // Create a queue and enqueue root Queue<Node> q = new LinkedList<>(); Node curr = root.child; q.add(curr); while (!q.isEmpty()) { // Take out an item from the queue curr = q.peek(); q.remove(); // Print next level of taken out item and enqueue // next level's children while (curr != null ) { System.out.print(curr.data + " " ); if (curr.child != null ) { q.add(curr.child); } curr = curr.next; } } } // Driver code public static void main(String[] args) { Node root = newNode( 10 ); Node n1 = addChild(root, 2 ); Node n2 = addChild(root, 3 ); Node n3 = addChild(root, 4 ); Node n4 = addChild(n3, 6 ); Node n5 = addChild(root, 5 ); Node n6 = addChild(n5, 7 ); Node n7 = addChild(n5, 8 ); Node n8 = addChild(n5, 9 ); traverseTree(root); } } // This code is contributed by aashish1995 |
Python3
# Python3 program to create a tree with # left child right sibling representation from collections import deque class Node: def __init__( self , x): self .data = x self . next = None self .child = None # Adds a sibling to a list with # starting with n def addSibling(n, data): if (n = = None ): return None while (n. next ): n = n. next n. next = Node(data) return n # Add child Node to a Node def addChild(n, data): if (n = = None ): return None # Check if child list is not empty if (n.child): return addSibling(n.child, data) else : n.child = Node(data) return n # Traverses tree in level order def traverseTree(root): # Corner cases if (root = = None ): return print (root.data, end = " " ) if (root.child = = None ): return # Create a queue and enqueue root q = deque() curr = root.child q.append(curr) while ( len (q) > 0 ): # Take out an item from the queue curr = q.popleft() #q.pop() # Print next level of taken out # item and enqueue next level's children while (curr ! = None ): print (curr.data, end = " " ) if (curr.child ! = None ): q.append(curr.child) curr = curr. next # Driver code if __name__ = = '__main__' : root = Node( 10 ) n1 = addChild(root, 2 ) n2 = addChild(root, 3 ) n3 = addChild(root, 4 ) n4 = addChild(n3, 6 ) n5 = addChild(root, 5 ) n6 = addChild(n5, 7 ) n7 = addChild(n5, 8 ) n8 = addChild(n5, 9 ) traverseTree(root) # This code is contributed by mohit kumar 29 |
C#
// C# program to create a tree with left child // right sibling representation. using System; using System.Collections.Generic; class GFG { public class Node { public int data; public Node next; public Node child; }; // Creating new Node static Node newNode( int data) { Node newNode = new Node(); newNode.next = newNode.child = null ; newNode.data = data; return newNode; } // Adds a sibling to a list with starting with n static Node addSibling(Node n, int data) { if (n == null ) return null ; while (n.next != null ) n = n.next; return (n.next = newNode(data)); } // Add child Node to a Node static Node addChild(Node n, int data) { if (n == null ) return null ; // Check if child list is not empty. if (n.child != null ) return addSibling(n.child, data); else return (n.child = newNode(data)); } // Traverses tree in level order static void traverseTree(Node root) { // Corner cases if (root == null ) return ; Console.Write(root.data + " " ); if (root.child == null ) return ; // Create a queue and enqueue root Queue<Node> q = new Queue<Node>(); Node curr = root.child; q.Enqueue(curr); while (q.Count != 0) { // Take out an item from the queue curr = q.Peek(); q.Dequeue(); // Print next level of taken out item and enqueue // next level's children while (curr != null ) { Console.Write(curr.data + " " ); if (curr.child != null ) { q.Enqueue(curr.child); } curr = curr.next; } } } // Driver code public static void Main(String[] args) { Node root = newNode(10); Node n1 = addChild(root, 2); Node n2 = addChild(root, 3); Node n3 = addChild(root, 4); Node n4 = addChild(n3, 6); Node n5 = addChild(root, 5); Node n6 = addChild(n5, 7); Node n7 = addChild(n5, 8); Node n8 = addChild(n5, 9); traverseTree(root); } } // This code is contributed by Rajput-Ji |
Javascript
<script> // JavaScript program to create a // tree with left child // right sibling representation. class Node { // Creating new Node constructor(data) { this .data=data; this .next = this .child = null ; } } // Adds a sibling to a list with starting with n function addSibling(n,data) { if (n == null ) return null ; while (n.next != null ) n = n.next; return (n.next = new Node(data)); } // Add child Node to a Node function addChild(n,data) { if (n == null ) return null ; // Check if child list is not empty. if (n.child != null ) return addSibling(n.child, data); else return (n.child = new Node(data)); } // Traverses tree in level order function traverseTree(root) { // Corner cases if (root == null ) return ; document.write(root.data+ " " ); if (root.child == null ) return ; // Create a queue and enqueue root let q = []; let curr = root.child; q.push(curr); while (q.length!=0) { // Take out an item from the queue curr = q[0]; q.shift(); // Print next level of taken out item and enqueue // next level's children while (curr != null ) { document.write(curr.data + " " ); if (curr.child != null ) { q.push(curr.child); } curr = curr.next; } } } // Driver code let root = new Node(10); let n1 = addChild(root, 2); let n2 = addChild(root, 3); let n3 = addChild(root, 4); let n4 = addChild(n3, 6); let n5 = addChild(root, 5); let n6 = addChild(n5, 7); let n7 = addChild(n5, 8); let n8 = addChild(n5, 9); traverseTree(root); // This code is contributed by unknown2108 </script> |
10 2 3 4 5 6 7 8 9
Time Complexity: O(n), where n is the number of nodes in the tree.
Auxiliary Space: O(n)
If you like w3wiki(We know you do!) and would like to contribute, you can also write an article using write.w3wiki.net or mail your article to review-team@w3wiki.net.
Contact Us