Converteer een binaire boom naar een circulaire dubbellinklijst

Converteer een binaire boom naar een circulaire dubbellinklijst
Probeer het eens op GfG Practice boom om op te noemen #practiceLinkDiv {weergave: geen! belangrijk; }

Gegeven een Binaire boom converteer het naar een Circulaire dubbelgekoppelde lijst (ter plaatse).  

  • De linker- en rechteraanwijzers in knooppunten moeten worden gebruikt als respectievelijk vorige en volgende aanwijzers in de geconverteerde Circular Linked List.
  • De volgorde van de knooppunten in de lijst moet dezelfde zijn als in de volgorde voor de gegeven binaire boom.
  • Het eerste knooppunt van Inorder-traversal moet het hoofdknooppunt van de Circulaire Lijst zijn.

Voorbeelden:

Aanbevolen praktijk Binaire boom naar CDLL Probeer het!

Converteer een binaire boom naar een circulaire dubbellinklijst met behulp van recursie:

Het idee is om een ​​functie voor algemeen gebruik te maken die twee gegeven cirkelvormige dubbellijsten samenvoegt

Volg de onderstaande stappen om het probleem op te lossen:

  • Converteer de linker subboom recursief naar een cirkelvormige DLL. Laat de geconverteerde lijst zijn linkerLijst .
  • Converteer de rechter subboom recursief naar een cirkelvormige DLL. Laat de geconverteerde lijst zijn juisteLijst
  • Maak een cirkelvormig gekoppelde lijst met wortels van de boom en zorg ervoor dat de linker- en rechterwortel naar zichzelf verwijzen. 
  • Samenvoegen linkerLijst met de lijst van het enkele hoofdknooppunt. 
  • Voeg de lijst die in de bovenstaande stap is gemaakt samen met juisteLijst .

Opmerking: De bovenstaande benadering doorkruist de boom op een Postorder-manier. We kunnen ook op een ongeordende manier doorkruisen. We kunnen eerst de linker subboom en de wortel aaneenschakelen en dan terugkeren voor de rechter subboom en het resultaat aaneenschakelen met de linker-wortel aaneenschakeling.

Hoe kunnen twee circulaire DLL's aaneengeschakeld worden?  

  • Haal het laatste knooppunt van de linkerlijst op. Het ophalen van het laatste knooppunt is een O(1)-bewerking, aangezien de vorige aanwijzer van het hoofd naar het laatste knooppunt van de lijst wijst.
  • Verbind het met het eerste knooppunt van de juiste lijst
  • Haal het laatste knooppunt van de tweede lijst op
  • Verbind het met de kop van de lijst.

Hieronder staan ​​​​implementaties van het bovenstaande idee:

C++
   // C++ Program to convert a Binary Tree   // to a Circular Doubly Linked List   #include          using     namespace     std  ;   // To represents a node of a Binary Tree   struct     Node     {      struct     Node     *  left       *  right  ;      int     data  ;   };   // A function that appends rightList at the end   // of leftList.   Node  *     concatenate  (  Node  *     leftList       Node  *     rightList  )   {      // If either of the list is empty      // then return the other list      if     (  leftList     ==     NULL  )      return     rightList  ;      if     (  rightList     ==     NULL  )      return     leftList  ;      // Store the last Node of left List      Node  *     leftLast     =     leftList  ->  left  ;      // Store the last Node of right List      Node  *     rightLast     =     rightList  ->  left  ;      // Connect the last node of Left List      // with the first Node of the right List      leftLast  ->  right     =     rightList  ;      rightList  ->  left     =     leftLast  ;      // Left of first node points to      // the last node in the list      leftList  ->  left     =     rightLast  ;      // Right of last node refers to the first      // node of the List      rightLast  ->  right     =     leftList  ;      return     leftList  ;   }   // Function converts a tree to a circular Linked List   // and then returns the head of the Linked List   Node  *     bTreeToCList  (  Node  *     root  )   {      if     (  root     ==     NULL  )      return     NULL  ;      // Recursively convert left and right subtrees      Node  *     left     =     bTreeToCList  (  root  ->  left  );      Node  *     right     =     bTreeToCList  (  root  ->  right  );      // Make a circular linked list of single node      // (or root). To do so make the right and      // left pointers of this node point to itself      root  ->  left     =     root  ->  right     =     root  ;      // Step 1 (concatenate the left list with the list      // with single node i.e. current node)      // Step 2 (concatenate the returned list with the      // right List)      return     concatenate  (  concatenate  (  left       root  )     right  );   }   // Display Circular Link List   void     displayCList  (  Node  *     head  )   {      cout      < <     'Circular Linked List is :  n  '  ;      Node  *     itr     =     head  ;      do     {      cout      < <     itr  ->  data      < <     ' '  ;      itr     =     itr  ->  right  ;      }     while     (  head     !=     itr  );      cout      < <     '  n  '  ;   }   // Create a new Node and return its address   Node  *     newNode  (  int     data  )   {      Node  *     temp     =     new     Node  ();      temp  ->  data     =     data  ;      temp  ->  left     =     temp  ->  right     =     NULL  ;      return     temp  ;   }   // Driver Program to test above function   int     main  ()   {      Node  *     root     =     newNode  (  10  );      root  ->  left     =     newNode  (  12  );      root  ->  right     =     newNode  (  15  );      root  ->  left  ->  left     =     newNode  (  25  );      root  ->  left  ->  right     =     newNode  (  30  );      root  ->  right  ->  left     =     newNode  (  36  );      Node  *     head     =     bTreeToCList  (  root  );      displayCList  (  head  );      return     0  ;   }   // This code is contributed by Aditya Kumar (adityakumar129)   
C
   // C Program to convert a Binary Tree   // to a Circular Doubly Linked List   #include         #include         // To represents a node of a Binary Tree   typedef     struct     Node     {      struct     Node     *  left       *  right  ;      int     data  ;   }     Node  ;   // A function that appends rightList at the end   // of leftList.   Node  *     concatenate  (  Node  *     leftList       Node  *     rightList  )   {      // If either of the list is empty      // then return the other list      if     (  leftList     ==     NULL  )      return     rightList  ;      if     (  rightList     ==     NULL  )      return     leftList  ;      // Store the last Node of left List      Node  *     leftLast     =     leftList  ->  left  ;      // Store the last Node of right List      Node  *     rightLast     =     rightList  ->  left  ;      // Connect the last node of Left List      // with the first Node of the right List      leftLast  ->  right     =     rightList  ;      rightList  ->  left     =     leftLast  ;      // Left of first node points to      // the last node in the list      leftList  ->  left     =     rightLast  ;      // Right of last node refers to the first      // node of the List      rightLast  ->  right     =     leftList  ;      return     leftList  ;   }   // Function converts a tree to a circular Linked List   // and then returns the head of the Linked List   Node  *     bTreeToCList  (  Node  *     root  )   {      if     (  root     ==     NULL  )      return     NULL  ;      // Recursively convert left and right subtrees      Node  *     left     =     bTreeToCList  (  root  ->  left  );      Node  *     right     =     bTreeToCList  (  root  ->  right  );      // Make a circular linked list of single node      // (or root). To do so make the right and      // left pointers of this node point to itself      root  ->  left     =     root  ->  right     =     root  ;      // Step 1 (concatenate the left list with the list      // with single node i.e. current node)      // Step 2 (concatenate the returned list with the      // right List)      return     concatenate  (  concatenate  (  left       root  )     right  );   }   // Display Circular Link List   void     displayCList  (  Node  *     head  )   {      printf  (  'Circular Linked List is :  n  '  );      Node  *     itr     =     head  ;      do     {      printf  (  '%d '       itr  ->  data  );      itr     =     itr  ->  right  ;      }     while     (  head     !=     itr  );      printf  (  '  n  '  );   }   // Create a new Node and return its address   Node  *     newNode  (  int     data  )   {      Node  *     temp     =     (  Node  *  )  malloc  (  sizeof  (  Node  ));      temp  ->  data     =     data  ;      temp  ->  left     =     temp  ->  right     =     NULL  ;      return     temp  ;   }   // Driver Program to test above function   int     main  ()   {      Node  *     root     =     newNode  (  10  );      root  ->  left     =     newNode  (  12  );      root  ->  right     =     newNode  (  15  );      root  ->  left  ->  left     =     newNode  (  25  );      root  ->  left  ->  right     =     newNode  (  30  );      root  ->  right  ->  left     =     newNode  (  36  );      Node  *     head     =     bTreeToCList  (  root  );      displayCList  (  head  );      return     0  ;   }   // This code is contributed by Aditya Kumar (adityakumar129)   
Java
   // Java Program to convert a Binary Tree to a   // Circular Doubly Linked List   // Node class represents a Node of a Tree   class   Node     {      int     val  ;      Node     left       right  ;      public     Node  (  int     val  )      {      this  .  val     =     val  ;      left     =     right     =     null  ;      }   }   // A class to represent a tree   class   Tree     {      Node     root  ;      public     Tree  ()     {     root     =     null  ;     }      // concatenate both the lists and returns the head      // of the List      public     Node     concatenate  (  Node     leftList       Node     rightList  )      {      // If either of the list is empty then      // return the other list      if     (  leftList     ==     null  )      return     rightList  ;      if     (  rightList     ==     null  )      return     leftList  ;      // Store the last Node of left List      Node     leftLast     =     leftList  .  left  ;      // Store the last Node of right List      Node     rightLast     =     rightList  .  left  ;      // Connect the last node of Left List      // with the first Node of the right List      leftLast  .  right     =     rightList  ;      rightList  .  left     =     leftLast  ;      // left of first node refers to      // the last node in the list      leftList  .  left     =     rightLast  ;      // Right of last node refers to the first      // node of the List      rightLast  .  right     =     leftList  ;      // Return the Head of the List      return     leftList  ;      }      // Method converts a tree to a circular      // Link List and then returns the head      // of the Link List      public     Node     bTreeToCList  (  Node     root  )      {      if     (  root     ==     null  )      return     null  ;      // Recursively convert left and right subtrees      Node     left     =     bTreeToCList  (  root  .  left  );      Node     right     =     bTreeToCList  (  root  .  right  );      // Make a circular linked list of single node      // (or root). To do so make the right and      // left pointers of this node point to itself      root  .  left     =     root  .  right     =     root  ;      // Step 1 (concatenate the left list with the list      // with single node i.e. current node)      // Step 2 (concatenate the returned list with the      // right List)      return     concatenate  (  concatenate  (  left       root  )     right  );      }      // Display Circular Link List      public     void     display  (  Node     head  )      {      System  .  out  .  println  (  'Circular Linked List is :'  );      Node     itr     =     head  ;      do     {      System  .  out  .  print  (  itr  .  val     +     ' '  );      itr     =     itr  .  right  ;      }     while     (  itr     !=     head  );      System  .  out  .  println  ();      }   }   // Driver Code   class   Main     {      public     static     void     main  (  String     args  []  )      {      // Build the tree      Tree     tree     =     new     Tree  ();      tree  .  root     =     new     Node  (  10  );      tree  .  root  .  left     =     new     Node  (  12  );      tree  .  root  .  right     =     new     Node  (  15  );      tree  .  root  .  left  .  left     =     new     Node  (  25  );      tree  .  root  .  left  .  right     =     new     Node  (  30  );      tree  .  root  .  right  .  left     =     new     Node  (  36  );      // head refers to the head of the Link List      Node     head     =     tree  .  bTreeToCList  (  tree  .  root  );      // Display the Circular LinkedList      tree  .  display  (  head  );      }   }   
Python3
   # Python3 Program to convert a Binary   # Tree to a Circular Doubly Linked List   class   newNode  :   def   __init__  (  self     data  ):   self  .  data   =   data   self  .  left   =   self  .  right   =   None   # A function that appends rightList   # at the end of leftList.   def   concatenate  (  leftList     rightList  ):   # If either of the list is empty   # then return the other list   if   (  leftList   ==   None  ):   return   rightList   if   (  rightList   ==   None  ):   return   leftList   # Store the last Node of left List   leftLast   =   leftList  .  left   # Store the last Node of right List   rightLast   =   rightList  .  left   # Connect the last node of Left List   # with the first Node of the right List   leftLast  .  right   =   rightList   rightList  .  left   =   leftLast   # Left of first node points to   # the last node in the list   leftList  .  left   =   rightLast   # Right of last node refers to   # the first node of the List   rightLast  .  right   =   leftList   return   leftList   # Function converts a tree to a circular   # Linked List and then returns the head   # of the Linked List   def   bTreeToCList  (  root  ):   if   (  root   ==   None  ):   return   None   # Recursively convert left and   # right subtrees   left   =   bTreeToCList  (  root  .  left  )   right   =   bTreeToCList  (  root  .  right  )   # Make a circular linked list of single   # node (or root). To do so make the   # right and left pointers of this node   # point to itself   root  .  left   =   root  .  right   =   root   # Step 1 (concatenate the left list   # with the list with single   # node i.e. current node)   # Step 2 (concatenate the returned list   # with the right List)   return   concatenate  (  concatenate  (  left     root  )   right  )   # Display Circular Link List   def   displayCList  (  head  ):   print  (  'Circular Linked List is :'  )   itr   =   head   first   =   1   while   (  head   !=   itr   or   first  ):   print  (  itr  .  data     end  =  ' '  )   itr   =   itr  .  right   first   =   0   print  ()   # Driver Code   if   __name__   ==   '__main__'  :   root   =   newNode  (  10  )   root  .  left   =   newNode  (  12  )   root  .  right   =   newNode  (  15  )   root  .  left  .  left   =   newNode  (  25  )   root  .  left  .  right   =   newNode  (  30  )   root  .  right  .  left   =   newNode  (  36  )   head   =   bTreeToCList  (  root  )   displayCList  (  head  )   # This code is contributed by PranchalK   
C#
   // C# Program to convert a Binary Tree   // to a Circular Doubly Linked List   using     System  ;   // Node class represents a Node of a Tree   public     class     Node     {      public     int     val  ;      public     Node     left       right  ;      public     Node  (  int     val  )      {      this  .  val     =     val  ;      left     =     right     =     null  ;      }   }   // A class to represent a tree   public     class     Tree     {      internal     Node     root  ;      public     Tree  ()     {     root     =     null  ;     }      // concatenate both the lists      // and returns the head of the List      public     virtual     Node     concatenate  (  Node     leftList        Node     rightList  )      {      // If either of the list is empty      // then return the other list      if     (  leftList     ==     null  )     {      return     rightList  ;      }      if     (  rightList     ==     null  )     {      return     leftList  ;      }      // Store the last Node of left List      Node     leftLast     =     leftList  .  left  ;      // Store the last Node of right List      Node     rightLast     =     rightList  .  left  ;      // Connect the last node of Left List      // with the first Node of the right List      leftLast  .  right     =     rightList  ;      rightList  .  left     =     leftLast  ;      // left of first node refers to      // the last node in the list      leftList  .  left     =     rightLast  ;      // Right of last node refers to      // the first node of the List      rightLast  .  right     =     leftList  ;      // Return the Head of the List      return     leftList  ;      }      // Method converts a tree to a circular      // Link List and then returns the head      // of the Link List      public     virtual     Node     bTreeToCList  (  Node     root  )      {      if     (  root     ==     null  )     {      return     null  ;      }      // Recursively convert left      // and right subtrees      Node     left     =     bTreeToCList  (  root  .  left  );      Node     right     =     bTreeToCList  (  root  .  right  );      // Make a circular linked list of single      // node (or root). To do so make the      // right and left pointers of this node      // point to itself      root  .  left     =     root  .  right     =     root  ;      // Step 1 (concatenate the left list with      // the list with single node      // i.e. current node)      // Step 2 (concatenate the returned list      // with the right List)      return     concatenate  (  concatenate  (  left       root  )     right  );      }      // Display Circular Link List      public     virtual     void     display  (  Node     head  )      {      Console  .  WriteLine  (  'Circular Linked List is :'  );      Node     itr     =     head  ;      do     {      Console  .  Write  (  itr  .  val     +     ' '  );      itr     =     itr  .  right  ;      }     while     (  itr     !=     head  );      Console  .  WriteLine  ();      }   }   // Driver Code   public     class     GFG     {      public     static     void     Main  (  string  []     args  )      {      // Build the tree      Tree     tree     =     new     Tree  ();      tree  .  root     =     new     Node  (  10  );      tree  .  root  .  left     =     new     Node  (  12  );      tree  .  root  .  right     =     new     Node  (  15  );      tree  .  root  .  left  .  left     =     new     Node  (  25  );      tree  .  root  .  left  .  right     =     new     Node  (  30  );      tree  .  root  .  right  .  left     =     new     Node  (  36  );      // head refers to the head of the Link List      Node     head     =     tree  .  bTreeToCList  (  tree  .  root  );      // Display the Circular LinkedList      tree  .  display  (  head  );      }   }   // This code is contributed by Shrikant13   
JavaScript
    <  script  >   // javascript Program to convert a Binary Tree to a   // Circular Doubly Linked List   // Node class represents a Node of a Tree   class     Node     {      constructor  (  val  )     {      this  .  val     =     val  ;      this  .  left     =     null  ;      this  .  right     =     null  ;      }   }   // A class to represent a       var     root     =     null  ;      // concatenate both the lists and returns the head      // of the List      function     concatenate  (  leftList       rightList  )     {      // If either of the list is empty then      // return the other list      if     (  leftList     ==     null  )      return     rightList  ;      if     (  rightList     ==     null  )      return     leftList  ;      // Store the last Node of left List      var     leftLast     =     leftList  .  left  ;      // Store the last Node of right List      var     rightLast     =     rightList  .  left  ;      // Connect the last node of Left List      // with the first Node of the right List      leftLast  .  right     =     rightList  ;      rightList  .  left     =     leftLast  ;      // left of first node refers to      // the last node in the list      leftList  .  left     =     rightLast  ;      // Right of last node refers to the first      // node of the List      rightLast  .  right     =     leftList  ;      // Return the Head of the List      return     leftList  ;      }      // Method converts a to a circular      // Link List and then returns the head      // of the Link List      function     bTreeToCList  (  root  )     {      if     (  root     ==     null  )      return     null  ;      // Recursively convert left and right subtrees      var     left     =     bTreeToCList  (  root  .  left  );      var     right     =     bTreeToCList  (  root  .  right  );      // Make a circular linked list of single node      // (or root). To do so make the right and      // left pointers of this node point to itself      root  .  left     =     root  .  right     =     root  ;      // Step 1 (concatenate the left list with the list      // with single node i.e. current node)      // Step 2 (concatenate the returned list with the      // right List)      return     concatenate  (  concatenate  (  left       root  )     right  );      }      // Display Circular Link List      function     display  (  head  )     {      document  .  write  (  'Circular Linked List is :  
'
); var itr = head ; do { document . write ( itr . val + ' ' ); itr = itr . right ; } while ( itr != head ); document . write (); } // Driver Code // Build the root = new Node ( 10 ); root . left = new Node ( 12 ); root . right = new Node ( 15 ); root . left . left = new Node ( 25 ); root . left . right = new Node ( 30 ); root . right . left = new Node ( 36 ); // head refers to the head of the Link List var head = bTreeToCList ( root ); // Display the Circular LinkedList display ( head ); // This code contributed by umadevi9616 < /script>

Uitvoer
Circular Linked List is : 25 12 30 10 36 15  

Tijdcomplexiteit: OP) Omdat elk knooppunt maximaal één keer wordt bezocht.
Hulpruimte: O(log N) De extra ruimte wordt gebruikt in de recursieaanroepstapel, die kan uitgroeien tot een maximale grootte van logN omdat het een binaire boom is.

Converteer een binaire boom naar een circulaire dubbellinklijst door inorder-traversal:

Het idee is om de binaire boom in volgorde te doorlopen. Houd tijdens het doorlopen van de volgorde het eerder bezochte knooppunt in een variabele bij, bijvoorbeeld vorige . Maak van elk bezocht knooppunt het volgende knooppunt vorige en stel de vorige van dit knooppunt in als vorige .

Volg de onderstaande stappen om het probleem op te lossen:

  • Converteer eerst de binaire boom naar een dubbel gekoppelde lijst, raadpleeg dit bericht Converteer een bepaalde binaire boom naar een dubbel gekoppelde lijst .
  • Converteer nu deze dubbelgekoppelde lijst naar een cirkelvormige dubbelgekoppelde lijst door het eerste en het laatste knooppunt met elkaar te verbinden.

Hieronder vindt u de implementatie van bovenstaande aanpak.

C++
   // A C++ program for in-place conversion of Binary Tree to   // CDLL   #include          using     namespace     std  ;   /* A binary tree node has - data  left and right pointers    */   struct     Node     {      int     data  ;      Node  *     left  ;      Node  *     right  ;   };   // A utility function that converts given binary tree to   // a doubly linked list   // root --> the root of the binary tree   // head --> head of the created doubly linked list   Node  *     BTree2DoublyLinkedList  (  Node  *     root       Node  **     head  )   {      // Base case      if     (  root     ==     NULL  )      return     root  ;      // Initialize previously visited node as NULL. This is      // static so that the same value is accessible in all      // recursive calls      static     Node  *     prev     =     NULL  ;      // Recursively convert left subtree      BTree2DoublyLinkedList  (  root  ->  left       head  );      // Now convert this node      if     (  prev     ==     NULL  )      *  head     =     root  ;      else     {      root  ->  left     =     prev  ;      prev  ->  right     =     root  ;      }      prev     =     root  ;      // Finally convert right subtree      BTree2DoublyLinkedList  (  root  ->  right       head  );      return     prev  ;   }   // A simple recursive function to convert a given Binary   // tree to Circular Doubly Linked List using a utility   // function root --> Root of Binary Tree tail --> Pointer to   // tail node of created circular doubly linked list   Node  *     BTree2CircularDoublyLinkedList  (  Node  *     root  )   {      Node  *     head     =     NULL  ;      Node  *     tail     =     BTree2DoublyLinkedList  (  root       &  head  );      // make the changes to convert a DLL to CDLL      tail  ->  right     =     head  ;      head  ->  left     =     tail  ;      // return the head of the created CDLL      return     head  ;   }   /* Helper function that allocates a new node with the   given data and NULL left and right pointers. */   Node  *     newNode  (  int     data  )   {      Node  *     new_node     =     new     Node  ;      new_node  ->  data     =     data  ;      new_node  ->  left     =     new_node  ->  right     =     NULL  ;      return     (  new_node  );   }   /* Function to print nodes in a given circular doubly linked    * list */   void     printList  (  Node  *     head  )   {      if     (  head     ==     NULL  )      return  ;      Node  *     ptr     =     head  ;      do     {      cout      < <     ptr  ->  data      < <     ' '  ;      ptr     =     ptr  ->  right  ;      }     while     (  ptr     !=     head  );   }   /* Driver program to test above functions*/   int     main  ()   {      // Let us create the tree shown in above diagram      Node  *     root     =     newNode  (  10  );      root  ->  left     =     newNode  (  12  );      root  ->  right     =     newNode  (  15  );      root  ->  left  ->  left     =     newNode  (  25  );      root  ->  left  ->  right     =     newNode  (  30  );      root  ->  right  ->  left     =     newNode  (  36  );      // Convert to DLL      Node  *     head     =     BTree2CircularDoublyLinkedList  (  root  );      // Print the converted list      printList  (  head  );      return     0  ;   }   // This code was contributed by Abhijeet   // Kumar(abhijeet19403)   
Java
   // A Java program for in-place conversion of Binary Tree to   // CDLL   // A binary tree node has - data left pointer and right   // pointer   class   Node     {      int     data  ;      Node     left       right  ;      public     Node  (  int     data  )      {      this  .  data     =     data  ;      left     =     right     =     null  ;      }   }   class   BinaryTree     {      Node     root  ;      // head --> Pointer to head node of created doubly      // linked list      Node     head  ;      // Initialize previously visited node as NULL. This is      // static so that the same value is accessible in all      // recursive calls      static     Node     prev     =     null  ;      // A simple utility recursive function to convert a      // given Binary tree to Doubly Linked List root --> Root      // of Binary Tree      void     BTree2DoublyLinkedList  (  Node     root  )      {      // Base case      if     (  root     ==     null  )      return  ;      // Recursively convert left subtree      BTree2DoublyLinkedList  (  root  .  left  );      // Now convert this node      if     (  prev     ==     null  )      head     =     root  ;      else     {      root  .  left     =     prev  ;      prev  .  right     =     root  ;      }      prev     =     root  ;      // Finally convert right subtree      BTree2DoublyLinkedList  (  root  .  right  );      }      // A simple function to convert a given binary tree to      // Circular doubly linked list      // using a utility function      void     BTree2CircularDoublyLinkedList  (  Node     root  )      {      BTree2DoublyLinkedList  (  root  );      // make the changes to convert a DLL to CDLL      prev  .  right     =     head  ;      head  .  left     =     prev  ;      }      /* Function to print nodes in a given doubly linked list    */      void     printList  (  Node     node  )      {      if     (  node     ==     null  )      return  ;      Node     curr     =     node  ;      do     {      System  .  out  .  print  (  curr  .  data     +     ' '  );      curr     =     curr  .  right  ;      }     while     (  curr     !=     node  );      }      // Driver program to test above functions      public     static     void     main  (  String  []     args  )      {      // Let us create the tree as shown in above diagram      BinaryTree     tree     =     new     BinaryTree  ();      tree  .  root     =     new     Node  (  10  );      tree  .  root  .  left     =     new     Node  (  12  );      tree  .  root  .  right     =     new     Node  (  15  );      tree  .  root  .  left  .  left     =     new     Node  (  25  );      tree  .  root  .  left  .  right     =     new     Node  (  30  );      tree  .  root  .  right  .  left     =     new     Node  (  36  );      // convert to DLL      tree  .  BTree2CircularDoublyLinkedList  (  tree  .  root  );      // Print the converted List      tree  .  printList  (  tree  .  head  );      }   }   // This code has been contributed by Abhijeet   // Kumar(abhijeet19403)   
Python
   # A python program for in-place conversion of Binary Tree to DLL   # A binary tree node has data left pointers and right pointers   class   Node  :   def   __init__  (  self     val  ):   self  .  data   =   val   self  .  left   =   None   self  .  right   =   None   # head --> Pointer to head node of created doubly linked list   head   =   None   # Initialize previously visited node as NULL. This is   # so that the same value is accessible in all recursive   # calls   prev   =   None   # A simple recursive function to convert a given Binary tree   # to Doubly Linked List   # root --> Root of Binary Tree   def   BinaryTree2DoubleLinkedList  (  root  ):   # Base case   if   (  root   ==   None  ):   return   # Recursively convert left subtree   BinaryTree2DoubleLinkedList  (  root  .  left  )   # Now convert this node   global   prev     head   if   (  prev   ==   None  ):   head   =   root   else  :   root  .  left   =   prev   prev  .  right   =   root   prev   =   root   # Finally convert right subtree   BinaryTree2DoubleLinkedList  (  root  .  right  )   # Function to print nodes in a given doubly linked list   def   printList  (  node  ):   while   (  node   !=   None  ):   print  (  node  .  data  )   node   =   node  .  right   # Driver program to test above functions   # Let us create the tree as shown in above diagram   root   =   Node  (  10  )   root  .  left   =   Node  (  12  )   root  .  right   =   Node  (  15  )   root  .  left  .  left   =   Node  (  25  )   root  .  left  .  right   =   Node  (  30  )   root  .  right  .  left   =   Node  (  36  )   # convert to DLL   BinaryTree2DoubleLinkedList  (  root  )   # Print the converted List   printList  (  head  )   # This code is contributed by adityamaharshi21.   
C#
   // A C# program for in-place conversion of Binary Tree to   // CDLL   using     System  ;   public     class     Node     {      public     int     data  ;      public     Node     left       right  ;      public     Node  (  int     data  )      {      this  .  data     =     data  ;      left     =     right     =     null  ;      }   }   public     class     BinaryTree     {      Node     root  ;      // head --> Pointer to head node of created doubly      // linked list      Node     head  ;      // Initialize previously visited node as NULL. This is      // static so that the same value is accessible in all      // recursive calls      static     Node     prev     =     null  ;      // A simple utility recursive function to convert a      // given Binary tree to Doubly Linked List root --> Root      // of Binary Tree      void     BTree2DoublyLinkedList  (  Node     root  )      {      // Base case      if     (  root     ==     null  )      return  ;      // Recursively convert left subtree      BTree2DoublyLinkedList  (  root  .  left  );      // Now convert this node      if     (  prev     ==     null  )      head     =     root  ;      else     {      root  .  left     =     prev  ;      prev  .  right     =     root  ;      }      prev     =     root  ;      // Finally convert right subtree      BTree2DoublyLinkedList  (  root  .  right  );      }      // A simple function to convert a given binary tree to      // Circular doubly linked list      // using a utility function      void     BTree2CircularDoublyLinkedList  (  Node     root  )      {      BTree2DoublyLinkedList  (  root  );      // make the changes to convert a DLL to CDLL      prev  .  right     =     head  ;      head  .  left     =     prev  ;      }      /* Function to print nodes in a given doubly linked list    */      void     printList  (  Node     node  )      {      if     (  node     ==     null  )      return  ;      Node     curr     =     node  ;      do     {      Console  .  Write  (  curr  .  data     +     ' '  );      curr     =     curr  .  right  ;      }     while     (  curr     !=     node  );      }      static     public     void     Main  ()      {      // Let us create the tree as shown in above diagram      BinaryTree     tree     =     new     BinaryTree  ();      tree  .  root     =     new     Node  (  10  );      tree  .  root  .  left     =     new     Node  (  12  );      tree  .  root  .  right     =     new     Node  (  15  );      tree  .  root  .  left  .  left     =     new     Node  (  25  );      tree  .  root  .  left  .  right     =     new     Node  (  30  );      tree  .  root  .  right  .  left     =     new     Node  (  36  );      // convert to DLL      tree  .  BTree2CircularDoublyLinkedList  (  tree  .  root  );      // Print the converted List      tree  .  printList  (  tree  .  head  );      }   }   // This code is contributed by lokesh(lokeshmvs21).   
JavaScript
   // A javascript program for in-place conversion of Binary Tree to DLL   // A binary tree node has data left pointers and right pointers   class     Node     {      constructor  (  val  )     {      this  .  data     =     val  ;      this  .  left     =     null  ;      this  .  right     =     null  ;      }   }   var     root  ;   // head --> Pointer to head node of created doubly linked list   var     head  ;   // Initialize previously visited node as NULL. This is   // so that the same value is accessible in all recursive   // calls   var     prev     =     null  ;   // A simple recursive function to convert a given Binary tree   // to Doubly Linked List   // root --> Root of Binary Tree   function     BinaryTree2DoubleLinkedList  (  root  )   {      // Base case      if     (  root     ==     null  )      return  ;          // Recursively convert left subtree      BinaryTree2DoubleLinkedList  (  root  .  left  );          // Now convert this node      if     (  prev     ==     null  )      head     =     root  ;      else     {      root  .  left     =     prev  ;      prev  .  right     =     root  ;      }      prev     =     root  ;          // Finally convert right subtree      BinaryTree2DoubleLinkedList  (  root  .  right  );   }   /* Function to print nodes in a given doubly linked list */   function     printList  (  node  )     {      while     (  node     !=     null  )     {      console  .  log  (  node  .  data     +     ' '  );      node     =     node  .  right  ;      }   }   // Driver program to test above functions   // Let us create the tree as shown in above diagram   root     =     new     Node  (  10  );   root  .  left     =     new     Node  (  12  );   root  .  right     =     new     Node  (  15  );   root  .  left  .  left     =     new     Node  (  25  );   root  .  left  .  right     =     new     Node  (  30  );   root  .  right  .  left     =     new     Node  (  36  );   // convert to DLL   BinaryTree2DoubleLinkedList  (  root  );   // Print the converted List   printList  (  head  );   // This code is contributed by ishankhandelwals.   

Uitvoer
25 12 30 10 36 15  

Tijdcomplexiteit: O(N) Omdat elk knooppunt maximaal één keer wordt bezocht.
Hulpruimte: O(log N) De extra ruimte wordt gebruikt in de recursieve functieaanroepstapel, die kan uitgroeien tot een maximale grootte van logN.

Deze aanpak werd bijgedragen door Abhijeet Kumar