Izravnajte večnivojski povezani seznam (po globini)
Glede na povezan seznam, kjer je poleg naslednji kazalec, vsako vozlišče ima a otrok kazalec, ki lahko kaže ali ne kaže na ločen seznam. Ti podrejeni seznami lahko imajo enega ali več lastni otroci za proizvodnjo a večnivojski povezan seznam. Glede na glavo od prva stopnja seznama. Naloga je, da sploščiti seznamu, tako da so vsa vozlišča prikazana v a enonivojski povezan seznam. Izravnajte seznam na način, da bodo vsa vozlišča na prva stopnja bi moral priti prvi nato vozlišča drugo raven in tako naprej.
Primeri:
Vnos:
Izhod: 1->4->6->2->5->7->3->8
Pojasnilo: Večnivojski povezani seznam je sploščen, saj nima podrejenih kazalcev.
Razpravljali smo sploščitev večnivojskega povezanega seznama kjer imajo vozlišča dva kazalca navzdol in naprej. V prejšnji objavi smo sploščena povezani seznam nivojsko. Kako sploščiti povezan seznam, ko moramo vedno obdelati kazalec navzdol pred naslednjim na vsakem vozlišču.
Kazalo vsebine
- [Pričakovani pristop] Uporaba rekurzije - O(n) časa in O(n) prostora
- [Nadomestni pristop] Uporaba sklada - O(n) časa in O(n) prostora
[Pričakovani pristop] Uporaba rekurzije - O(n) časa in O(n) prostora
C++Pristop je k rekurzivno sploščiti a povezana na več ravneh seznam tako, da prečka vsako vozlišče in njegova podrejena vozlišča. najprej izravnajte podrejeni seznam z uporabo rekurzije. Ko je podrejeni seznam sploščen, nadaljujte z naslednje vozlišče v zaporedju. Med prečkanjem vzdržujte a referenca do predhodno obiskano vozlišče in ga povežite s trenutnim vozliščem. Ta postopek zagotavlja, da so vsa vozlišča z različnih ravni povezana v a enojni linearni seznam ob ohranjanju globinski red.
// A C++ program to flatten a multi- // linked list depth-wise #include using namespace std ; class Node { public : int data ; Node * next ; Node * down ; Node ( int x ) { data = x ; next = down = nullptr ; } }; void flattenList ( Node * curr Node *& prev ) { if ( curr == nullptr ) return ; // Add the current element to the list. if ( prev != nullptr ) prev -> next = curr ; prev = curr ; // Store the next pointer Node * next = curr -> next ; // Recursively add the bottom list flattenList ( curr -> down prev ); // Recursively add the next list flattenList ( next prev ); } void printList ( Node * head ) { Node * curr = head ; while ( curr != nullptr ) { cout < < curr -> data < < ' ' ; curr = curr -> next ; } cout < < endl ; } int main () { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node * head = new Node ( 5 ); head -> down = new Node ( 7 ); head -> down -> down = new Node ( 8 ); head -> down -> down -> down = new Node ( 30 ); head -> next = new Node ( 10 ); head -> next -> next = new Node ( 19 ); head -> next -> next -> down = new Node ( 22 ); head -> next -> next -> down -> down = new Node ( 50 ); head -> next -> next -> next = new Node ( 28 ); Node * prev = nullptr ; flattenList ( head prev ); printList ( head ); return 0 ; }
Java // A Java program to flatten a multi- // linked list depth-wise class Node { int data ; Node next down ; Node ( int x ) { data = x ; next = down = null ; } } class GfG { static void flattenList ( Node curr Node [] prev ) { if ( curr == null ) return ; // Add the current element to the list. if ( prev [ 0 ] != null ) prev [ 0 ] . next = curr ; prev [ 0 ] = curr ; // Store the next pointer Node next = curr . next ; // Recursively add the bottom list flattenList ( curr . down prev ); // Recursively add the next list flattenList ( next prev ); } static void printList ( Node head ) { Node curr = head ; while ( curr != null ) { System . out . print ( curr . data + ' ' ); curr = curr . next ; } System . out . println (); } public static void main ( String [] args ) { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); Node [] prev = new Node [ 1 ] ; flattenList ( head prev ); printList ( head ); } }
Python # A Python program to flatten a multi- # linked list depth-wise class Node : def __init__ ( self x ): self . data = x self . next = None self . down = None def flatten_list ( curr prev ): if curr is None : return # Add the current element to the list. if prev [ 0 ] is not None : prev [ 0 ] . next = curr prev [ 0 ] = curr # Store the next pointer next_node = curr . next # Recursively add the bottom list flatten_list ( curr . down prev ) # Recursively add the next list flatten_list ( next_node prev ) def print_list ( head ): curr = head while curr is not None : print ( curr . data end = ' ' ) curr = curr . next print () if __name__ == '__main__' : # Create a hard coded multi-linked list. # 5 -> 10 -> 19 -> 28 # | | # 7 22 # | | # 8 50 # | # 30 head = Node ( 5 ) head . down = Node ( 7 ) head . down . down = Node ( 8 ) head . down . down . down = Node ( 30 ) head . next = Node ( 10 ) head . next . next = Node ( 19 ) head . next . next . down = Node ( 22 ) head . next . next . down . down = Node ( 50 ) head . next . next . next = Node ( 28 ) prev = [ None ] flatten_list ( head prev ) print_list ( head )
C# // A C# program to flatten a multi- // linked list depth-wise using System ; class Node { public int data ; public Node next down ; public Node ( int x ) { data = x ; next = down = null ; } } class GfG { static void FlattenList ( Node curr ref Node prev ) { if ( curr == null ) return ; // Add the current element to the list. if ( prev != null ) prev . next = curr ; prev = curr ; // Store the next pointer Node next = curr . next ; // Recursively add the bottom list FlattenList ( curr . down ref prev ); // Recursively add the next list FlattenList ( next ref prev ); } static void PrintList ( Node head ) { Node curr = head ; while ( curr != null ) { Console . Write ( curr . data + ' ' ); curr = curr . next ; } Console . WriteLine (); } static void Main ( string [] args ) { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); Node prev = null ; FlattenList ( head ref prev ); PrintList ( head ); } }
JavaScript // A Javascript program to flatten a multi- // linked list depth-wise class Node { constructor ( x ) { this . data = x ; this . next = null ; this . down = null ; } } function flattenList ( curr prev ) { if ( curr === null ) return ; // Add the current element to the list. if ( prev [ 0 ] !== null ) prev [ 0 ]. next = curr ; prev [ 0 ] = curr ; // Store the next pointer let next = curr . next ; // Recursively add the bottom list flattenList ( curr . down prev ); // Recursively add the next list flattenList ( next prev ); } function printList ( head ) { let curr = head ; while ( curr !== null ) { console . log ( curr . data ); curr = curr . next ; } } // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 let head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); let prev = [ null ]; flattenList ( head prev ); printList ( head );
Izhod
5 7 8 30 10 19 22 50 28
[Nadomestni pristop] Uporaba sklada - O(n) časa in O(n) prostora
C++Pristop je prečkanje večnivojski povezani seznam z uporabo a kup . Začni z potiskanje the glavno vozlišče na sklad. Potem, medtem ko je sklad ni prazen pop zgornje vozlišče in ga obdelajte. Za vsako vozlišče potiskati njegov kazalca naprej in navzdol (če obstajajo) na sklad. Med tem procesom povezati trenutno vozlišče s prejšnjim vozliščem vzdrževanje seznama v sploščeni obliki. Prehod zagotavlja, da so vozlišča vseh ravni povezana v a enonivojski povezani seznam ohranjanje globinskega reda.
// A C++ program to flatten a multi- // linked list depth-wise using stack #include using namespace std ; class Node { public : int data ; Node * next ; Node * down ; Node ( int x ) { data = x ; next = down = nullptr ; } }; void flattenList ( Node * head ) { if ( head == nullptr ) return ; stack < Node *> st ; st . push ( head ); Node * prev = nullptr ; while ( ! st . empty ()) { Node * curr = st . top (); st . pop (); // Push the next node first if ( curr -> next != nullptr ) st . push ( curr -> next ); // Push the bottom node into stack if ( curr -> down != nullptr ) st . push ( curr -> down ); // Add the current element to the list if ( prev != nullptr ) prev -> next = curr ; prev = curr ; } } void printList ( Node * head ) { Node * curr = head ; while ( curr != nullptr ) { cout < < curr -> data < < ' ' ; curr = curr -> next ; } cout < < endl ; } int main () { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node * head = new Node ( 5 ); head -> down = new Node ( 7 ); head -> down -> down = new Node ( 8 ); head -> down -> down -> down = new Node ( 30 ); head -> next = new Node ( 10 ); head -> next -> next = new Node ( 19 ); head -> next -> next -> down = new Node ( 22 ); head -> next -> next -> down -> down = new Node ( 50 ); head -> next -> next -> next = new Node ( 28 ); flattenList ( head ); printList ( head ); return 0 ; }
Java // A Java program to flatten a multi- // linked list depth-wise using stack import java.util.Stack ; class Node { int data ; Node next down ; Node ( int x ) { data = x ; next = down = null ; } } class GfG { static void flattenList ( Node head ) { if ( head == null ) return ; Stack < Node > stack = new Stack <> (); stack . push ( head ); Node prev = null ; while ( ! stack . isEmpty ()) { Node curr = stack . pop (); // Push the next node first if ( curr . next != null ) stack . push ( curr . next ); // Push the bottom node into stack if ( curr . down != null ) stack . push ( curr . down ); // Add the current element to the list if ( prev != null ) prev . next = curr ; prev = curr ; } } static void printList ( Node head ) { Node curr = head ; while ( curr != null ) { System . out . print ( curr . data + ' ' ); curr = curr . next ; } System . out . println (); } public static void main ( String [] args ) { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); flattenList ( head ); printList ( head ); } }
Python # A Python program to flatten a multi- # linked list depth-wise using stack class Node : def __init__ ( self x ): self . data = x self . next = None self . down = None def flatten_list ( head ): if head is None : return stack = [ head ] prev = None while stack : curr = stack . pop () # Push the next node first if curr . next : stack . append ( curr . next ) # Push the bottom node into stack if curr . down : stack . append ( curr . down ) # Add the current element to the list if prev : prev . next = curr prev = curr def print_list ( head ): curr = head while curr : print ( curr . data end = ' ' ) curr = curr . next print () if __name__ == '__main__' : # Create a hard coded multi-linked list. # 5 -> 10 -> 19 -> 28 # | | # 7 22 # | | # 8 50 # | # 30 head = Node ( 5 ) head . down = Node ( 7 ) head . down . down = Node ( 8 ) head . down . down . down = Node ( 30 ) head . next = Node ( 10 ) head . next . next = Node ( 19 ) head . next . next . down = Node ( 22 ) head . next . next . down . down = Node ( 50 ) head . next . next . next = Node ( 28 ) flatten_list ( head ) print_list ( head )
C# // A C# program to flatten a multi- // linked list depth-wise using stack using System ; using System.Collections.Generic ; class Node { public int data ; public Node next down ; public Node ( int x ) { data = x ; next = down = null ; } } class GfG { static void FlattenList ( Node head ) { if ( head == null ) return ; Stack < Node > stack = new Stack < Node > (); stack . Push ( head ); Node prev = null ; while ( stack . Count > 0 ) { Node curr = stack . Pop (); // Push the next node first if ( curr . next != null ) stack . Push ( curr . next ); // Push the bottom node into stack if ( curr . down != null ) stack . Push ( curr . down ); // Add the current element to the list if ( prev != null ) prev . next = curr ; prev = curr ; } } static void PrintList ( Node head ) { Node curr = head ; while ( curr != null ) { Console . Write ( curr . data + ' ' ); curr = curr . next ; } Console . WriteLine (); } static void Main ( string [] args ) { // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 Node head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); FlattenList ( head ); PrintList ( head ); } }
JavaScript // A Javascript program to flatten a multi- // linked list depth-wise using stack class Node { constructor ( x ) { this . data = x ; this . next = null ; this . down = null ; } } function flattenList ( head ) { if ( head === null ) return ; let stack = [ head ]; let prev = null ; while ( stack . length > 0 ) { let curr = stack . pop (); // Push the next node first if ( curr . next !== null ) stack . push ( curr . next ); // Push the bottom node into stack if ( curr . down !== null ) stack . push ( curr . down ); // Add the current element to the list if ( prev !== null ) prev . next = curr ; prev = curr ; } } function printList ( head ) { let curr = head ; while ( curr !== null ) { console . log ( curr . data ); curr = curr . next ; } } // Create a hard coded multi-linked list. // 5 -> 10 -> 19 -> 28 // | | // 7 22 // | | // 8 50 // | // 30 let head = new Node ( 5 ); head . down = new Node ( 7 ); head . down . down = new Node ( 8 ); head . down . down . down = new Node ( 30 ); head . next = new Node ( 10 ); head . next . next = new Node ( 19 ); head . next . next . down = new Node ( 22 ); head . next . next . down . down = new Node ( 50 ); head . next . next . next = new Node ( 28 ); flattenList ( head ); printList ( head );
Izhod
5 7 8 30 10 19 22 50 28
