Grootste getal in BST dat kleiner is dan of gelijk is aan k

Grootste getal in BST dat kleiner is dan of gelijk is aan k

Gegeven de wortel van a Binaire zoekboom en een geheel getal k . De taak is om de grootste aantal in de binaire zoekboom dus minder dan of gelijkwaardig naar k als zo'n element niet bestaat, print -1. 

Voorbeelden:  

Invoer:

Grootste getal in BST dat kleiner is dan of gelijk is aan k-1

Uitgang: 21
Uitleg : 19 en 25 zijn de twee getallen die het dichtst bij 21 liggen en 19 is het grootste getal met een waarde kleiner dan of gelijk aan 21.

Invoer:

Grootste getal in BST dat kleiner is dan of gelijk is aan k-2

Uitgang: 3
Uitleg : 3 & 5 zijn de twee getallen die het dichtst bij 4 liggen en 3 is het grootste getal met een waarde kleiner dan of gelijk aan 4.

Inhoudsopgave

[Naïeve benadering] Recursie gebruiken - O(h) tijd en O(h) ruimte

Het idee is om te beginnen bij de wortel en vergelijk de waarde ervan met k. Als de waarde van het knooppunt groter is dan k, ga dan naar de linker subboom. Zoek anders de waarde van het grootste getal kleiner dan gelijk aan k in de rechter subboom . Als de rechter subboom -1 retourneert (wat betekent dat een dergelijke waarde niet bestaat), retourneert u de waarde van het huidige knooppunt. Anders retourneert u de waarde die wordt geretourneerd door de rechter subboom (aangezien deze groter zal zijn dan de waarde van het huidige knooppunt, maar kleiner dan gelijk aan k).

C++
   // C++ code to find the largest value    // smaller than or equal to k using recursion   #include          using     namespace     std  ;   class     Node     {   public  :      int     data  ;      Node     *  left       *  right  ;          Node  (  int     val  ){      data     =     val  ;      left     =     nullptr  ;      right     =     nullptr  ;      }   };   // function to find max value less than k   int     findMaxFork  (  Node  *     root       int     k  )     {          // Base cases      if     (  root     ==     nullptr  )      return     -1  ;      if     (  root  ->  data     ==     k  )      return     k  ;      // If root's value is smaller      // try in right subtree      else     if     (  root  ->  data      <     k  )     {          int     x     =     findMaxFork  (  root  ->  right       k  );      if     (  x     ==     -1  )      return     root  ->  data  ;      else      return     x  ;      }      // If root's data is greater       // return value from left subtree.      return     findMaxFork  (  root  ->  left       k  );      }   int     main  ()     {          int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node  *     root     =     new     Node  (  5  );      root  ->  left     =     new     Node  (  2  );      root  ->  left  ->  left     =     new     Node  (  1  );      root  ->  left  ->  right     =     new     Node  (  3  );      root  ->  right     =     new     Node  (  12  );      root  ->  right  ->  left     =     new     Node  (  9  );      root  ->  right  ->  right     =     new     Node  (  21  );      root  ->  right  ->  right  ->  left     =     new     Node  (  19  );      root  ->  right  ->  right  ->  right     =     new     Node  (  25  );          cout      < <     findMaxFork  (  root       k  );      return     0  ;   }   
Java
   // Java code to find the largest value    // smaller than or equal to k using recursion   class   Node     {      int     data  ;      Node     left       right  ;          Node  (  int     val  )     {      data     =     val  ;      left     =     null  ;      right     =     null  ;      }   }   class   GfG     {          // function to find max value less than k      static     int     findMaxFork  (  Node     root       int     k  )     {          // Base cases      if     (  root     ==     null  )      return     -  1  ;      if     (  root  .  data     ==     k  )      return     k  ;      // If root's value is smaller      // try in right subtree      else     if     (  root  .  data      <     k  )     {      int     x     =     findMaxFork  (  root  .  right       k  );      if     (  x     ==     -  1  )      return     root  .  data  ;      else      return     x  ;      }      // If root's data is greater      // return value from left subtree.      return     findMaxFork  (  root  .  left       k  );      }      public     static     void     main  (  String  []     args  )     {      int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node     root     =     new     Node  (  5  );      root  .  left     =     new     Node  (  2  );      root  .  left  .  left     =     new     Node  (  1  );      root  .  left  .  right     =     new     Node  (  3  );      root  .  right     =     new     Node  (  12  );      root  .  right  .  left     =     new     Node  (  9  );      root  .  right  .  right     =     new     Node  (  21  );      root  .  right  .  right  .  left     =     new     Node  (  19  );      root  .  right  .  right  .  right     =     new     Node  (  25  );      System  .  out  .  println  (  findMaxFork  (  root       k  ));      }   }   
Python
   # Python code to find the largest value    # smaller than or equal to k using recursion   class   Node  :   def   __init__  (  self     val  ):   self  .  data   =   val   self  .  left   =   None   self  .  right   =   None   # function to find max value less than k   def   findMaxFork  (  root     k  ):   # Base cases   if   root   is   None  :   return   -  1   if   root  .  data   ==   k  :   return   k   # If root's value is smaller   # try in right subtree   elif   root  .  data    <   k  :   x   =   findMaxFork  (  root  .  right     k  )   if   x   ==   -  1  :   return   root  .  data   else  :   return   x   # If root's data is greater   # return value from left subtree.   return   findMaxFork  (  root  .  left     k  )   if   __name__   ==   '__main__'  :   k   =   24   # creating following BST   #   # 5   # /     # 2 12   # /  /     # 1 3 9 21   # /     # 19 25   root   =   Node  (  5  )   root  .  left   =   Node  (  2  )   root  .  left  .  left   =   Node  (  1  )   root  .  left  .  right   =   Node  (  3  )   root  .  right   =   Node  (  12  )   root  .  right  .  left   =   Node  (  9  )   root  .  right  .  right   =   Node  (  21  )   root  .  right  .  right  .  left   =   Node  (  19  )   root  .  right  .  right  .  right   =   Node  (  25  )   print  (  findMaxFork  (  root     k  ))   
C#
   // C# code to find the largest value    // smaller than or equal to k using recursion   using     System  ;   class     Node     {      public     int     data  ;      public     Node     left       right  ;          public     Node  (  int     val  )     {      data     =     val  ;      left     =     null  ;      right     =     null  ;      }   }   class     GfG     {          // function to find max value less than k      static     int     FindMaxFork  (  Node     root       int     k  )     {          // Base cases      if     (  root     ==     null  )      return     -  1  ;      if     (  root  .  data     ==     k  )      return     k  ;      // If root's value is smaller      // try in right subtree      else     if     (  root  .  data      <     k  )     {      int     x     =     FindMaxFork  (  root  .  right       k  );      if     (  x     ==     -  1  )      return     root  .  data  ;      else      return     x  ;      }      // If root's data is greater      // return value from left subtree.      return     FindMaxFork  (  root  .  left       k  );      }      static     void     Main  ()     {      int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node     root     =     new     Node  (  5  );      root  .  left     =     new     Node  (  2  );      root  .  left  .  left     =     new     Node  (  1  );      root  .  left  .  right     =     new     Node  (  3  );      root  .  right     =     new     Node  (  12  );      root  .  right  .  left     =     new     Node  (  9  );      root  .  right  .  right     =     new     Node  (  21  );      root  .  right  .  right  .  left     =     new     Node  (  19  );      root  .  right  .  right  .  right     =     new     Node  (  25  );      Console  .  WriteLine  (  FindMaxFork  (  root       k  ));      }   }   
JavaScript
   // JavaScript code to find the largest value    // smaller than or equal to k using recursion   class     Node     {      constructor  (  val  )     {      this  .  data     =     val  ;      this  .  left     =     null  ;      this  .  right     =     null  ;      }   }   // function to find max value less than k   function     findMaxFork  (  root       k  )     {          // Base cases      if     (  root     ===     null  )      return     -  1  ;      if     (  root  .  data     ===     k  )      return     k  ;      // If root's value is smaller      // try in right subtree      else     if     (  root  .  data      <     k  )     {      let     x     =     findMaxFork  (  root  .  right       k  );      if     (  x     ===     -  1  )      return     root  .  data  ;      else      return     x  ;      }      // If root's data is greater      // return value from left subtree.      return     findMaxFork  (  root  .  left       k  );   }   let     k     =     24  ;   // creating following BST   //   // 5   // /     // 2 12   // /  /     // 1 3 9 21   // /     // 19 25   let     root     =     new     Node  (  5  );   root  .  left     =     new     Node  (  2  );   root  .  left  .  left     =     new     Node  (  1  );   root  .  left  .  right     =     new     Node  (  3  );   root  .  right     =     new     Node  (  12  );   root  .  right  .  left     =     new     Node  (  9  );   root  .  right  .  right     =     new     Node  (  21  );   root  .  right  .  right  .  left     =     new     Node  (  19  );   root  .  right  .  right  .  right     =     new     Node  (  25  );   console  .  log  (  findMaxFork  (  root       k  ));   

Uitvoer
21 

[Verwachte aanpak] Iteratie gebruiken - O(h) Tijd en O(1) Ruimte

Het idee is om te beginnen bij de wortel en vergelijk de waarde ervan met k . Als de waarde van het knooppunt is <= k werk de resultaatwaarde bij naar de waarde van root en ga naar de rechts subboom anders ga naar de links subboom. Door iteratief Door deze bewerking op alle knooppunten toe te passen, kunnen we de benodigde ruimte voor de recursie stapel.

C++
   // C++ code to find the largest value    // smaller than or equal to k using recursion   #include          using     namespace     std  ;   class     Node     {   public  :      int     data  ;      Node     *  left       *  right  ;          Node  (  int     val  ){      data     =     val  ;      left     =     nullptr  ;      right     =     nullptr  ;      }   };   // function to find max value less than k   int     findMaxFork  (  Node  *     root       int     k  )     {          int     result     =     -1  ;          // Start from root and keep looking for larger       while     (  root     !=     nullptr  )     {      // If root is smaller go to right side      if     (  root  ->  data      <=     k  ){      result     =     root  ->  data  ;      root     =     root  ->  right  ;      }      // If root is greater go to left side       else      root     =     root  ->  left  ;      }          return     result  ;   }   int     main  ()     {          int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node  *     root     =     new     Node  (  5  );      root  ->  left     =     new     Node  (  2  );      root  ->  left  ->  left     =     new     Node  (  1  );      root  ->  left  ->  right     =     new     Node  (  3  );      root  ->  right     =     new     Node  (  12  );      root  ->  right  ->  left     =     new     Node  (  9  );      root  ->  right  ->  right     =     new     Node  (  21  );      root  ->  right  ->  right  ->  left     =     new     Node  (  19  );      root  ->  right  ->  right  ->  right     =     new     Node  (  25  );          cout      < <     findMaxFork  (  root       k  );      return     0  ;   }   
Java
   // Java code to find the largest value    // smaller than or equal to k using recursion   class   Node     {      int     data  ;      Node     left       right  ;          Node  (  int     val  )     {      data     =     val  ;      left     =     null  ;      right     =     null  ;      }   }   class   GfG     {          // function to find max value less than k      static     int     findMaxFork  (  Node     root       int     k  )     {      int     result     =     -  1  ;          // Start from root and keep looking for larger       while     (  root     !=     null  )     {      // If root is smaller go to right side      if     (  root  .  data      <=     k  )     {      result     =     root  .  data  ;      root     =     root  .  right  ;      }      // If root is greater go to left side       else     {      root     =     root  .  left  ;      }      }          return     result  ;      }      public     static     void     main  (  String  []     args  )     {      int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node     root     =     new     Node  (  5  );      root  .  left     =     new     Node  (  2  );      root  .  left  .  left     =     new     Node  (  1  );      root  .  left  .  right     =     new     Node  (  3  );      root  .  right     =     new     Node  (  12  );      root  .  right  .  left     =     new     Node  (  9  );      root  .  right  .  right     =     new     Node  (  21  );      root  .  right  .  right  .  left     =     new     Node  (  19  );      root  .  right  .  right  .  right     =     new     Node  (  25  );      System  .  out  .  println  (  findMaxFork  (  root       k  ));      }   }   
Python
   # Python code to find the largest value    # smaller than or equal to k using recursion   class   Node  :   def   __init__  (  self     val  ):   self  .  data   =   val   self  .  left   =   None   self  .  right   =   None   # function to find max value less than k   def   findMaxFork  (  root     k  ):   result   =   -  1   # Start from root and keep looking for larger    while   root   is   not   None  :   # If root is smaller go to right side   if   root  .  data    <=   k  :   result   =   root  .  data   root   =   root  .  right   # If root is greater go to left side    else  :   root   =   root  .  left   return   result   if   __name__   ==   '__main__'  :   k   =   24   # creating following BST   #   # 5   # /     # 2 12   # /  /     # 1 3 9 21   # /     # 19 25   root   =   Node  (  5  )   root  .  left   =   Node  (  2  )   root  .  left  .  left   =   Node  (  1  )   root  .  left  .  right   =   Node  (  3  )   root  .  right   =   Node  (  12  )   root  .  right  .  left   =   Node  (  9  )   root  .  right  .  right   =   Node  (  21  )   root  .  right  .  right  .  left   =   Node  (  19  )   root  .  right  .  right  .  right   =   Node  (  25  )   print  (  findMaxFork  (  root     k  ))   
C#
   // C# code to find the largest value    // smaller than or equal to k using recursion   using     System  ;   class     Node     {      public     int     data  ;      public     Node     left       right  ;          public     Node  (  int     val  )     {      data     =     val  ;      left     =     null  ;      right     =     null  ;      }   }   class     GfG     {          // function to find max value less than k      static     int     FindMaxFork  (  Node     root       int     k  )     {      int     result     =     -  1  ;          // Start from root and keep looking for larger       while     (  root     !=     null  )     {      // If root is smaller go to right side      if     (  root  .  data      <=     k  )     {      result     =     root  .  data  ;      root     =     root  .  right  ;      }      // If root is greater go to left side       else     {      root     =     root  .  left  ;      }      }          return     result  ;      }      static     void     Main  ()     {      int     k     =     24  ;      // creating following BST      //      // 5      // /        // 2 12      // /  /        // 1 3 9 21      // /        // 19 25      Node     root     =     new     Node  (  5  );      root  .  left     =     new     Node  (  2  );      root  .  left  .  left     =     new     Node  (  1  );      root  .  left  .  right     =     new     Node  (  3  );      root  .  right     =     new     Node  (  12  );      root  .  right  .  left     =     new     Node  (  9  );      root  .  right  .  right     =     new     Node  (  21  );      root  .  right  .  right  .  left     =     new     Node  (  19  );      root  .  right  .  right  .  right     =     new     Node  (  25  );      Console  .  WriteLine  (  FindMaxFork  (  root       k  ));      }   }   
JavaScript
   // JavaScript code to find the largest value    // smaller than or equal to k using recursion   class     Node     {      constructor  (  val  )     {      this  .  data     =     val  ;      this  .  left     =     null  ;      this  .  right     =     null  ;      }   }   // function to find max value less than k   function     findMaxFork  (  root       k  )     {      let     result     =     -  1  ;          // Start from root and keep looking for larger       while     (  root     !==     null  )     {      // If root is smaller go to right side      if     (  root  .  data      <=     k  )     {      result     =     root  .  data  ;      root     =     root  .  right  ;      }      // If root is greater go to left side       else     {      root     =     root  .  left  ;      }      }          return     result  ;   }   let     k     =     24  ;   // creating following BST   //   // 5   // /     // 2 12   // /  /     // 1 3 9 21   // /     // 19 25   let     root     =     new     Node  (  5  );   root  .  left     =     new     Node  (  2  );   root  .  left  .  left     =     new     Node  (  1  );   root  .  left  .  right     =     new     Node  (  3  );   root  .  right     =     new     Node  (  12  );   root  .  right  .  left     =     new     Node  (  9  );   root  .  right  .  right     =     new     Node  (  21  );   root  .  right  .  right  .  left     =     new     Node  (  19  );   root  .  right  .  right  .  right     =     new     Node  (  25  );   console  .  log  (  findMaxFork  (  root       k  ));   

Uitvoer
21 
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