使用指针，在整个列表中循环，并使用特殊指针跟踪包含最后一个出现键的节点之前的节点。在此之后，只需将下一个特殊指针存储到下一个特殊指针中，即可从链表中删除所需的节点。
null
C++
#include <iostream> #include <bits/stdc++.h> using namespace std; // A linked list Node struct Node { int data; struct Node* next; }; // Function to delete the last occurrence void deleteLast( struct Node** head, int x) { struct Node** tmp1 = NULL; while (*head) { if ((*head)->data == x) { tmp1 = head; } head = &(*head)->next; } if (tmp1) { struct Node* tmp = *tmp1; *tmp1 = tmp->next; free (tmp); } } // Utility function to create a new node with // given key struct Node* newNode( int x) { Node* node = new Node ; node->data = x; node->next = NULL; return node; } // This function prints contents of linked // list starting from the given Node void display( struct Node* head) { struct Node* temp = head; if (head == NULL) { cout << "NULL" ; return ; } while (temp != NULL) { cout << temp->data << " --> " ; temp = temp->next; } cout << "NULL" ; } // Driver code int main() { struct Node* head = newNode(1); head->next = newNode(2); head->next->next = newNode(3); head->next->next->next = newNode(4); head->next->next->next->next = newNode(5); head->next->next->next->next->next = newNode(4); head->next->next->next->next->next->next = newNode(4); cout << "Created Linked list: " ; display(head); // Pass the address of the head pointer deleteLast(&head, 4); cout << "List after deletion of 4: " ; display(head); return 0; } // This code is contributed by khushboogoyal499 |
C
#include <stdio.h> #include <stdlib.h> // A linked list Node struct Node { int data; struct Node* next; }; // Function to delete the last occurrence void deleteLast( struct Node** head, int x) { struct Node** tmp1 = NULL; while (*head) { if ((*head)->data == x) { tmp1 = head; } head = &(*head)->next; } if (tmp1) { struct Node* tmp = *tmp1; *tmp1 = tmp->next; free (tmp); } } /* Utility function to create a new node with given key */ struct Node* newNode( int x) { struct Node* node = malloc ( sizeof ( struct Node*)); node->data = x; node->next = NULL; return node; } // This function prints contents of linked list // starting from the given Node void display( struct Node* head) { struct Node* temp = head; if (head == NULL) { printf ( "NULL" ); return ; } while (temp != NULL) { printf ( "%d --> " , temp->data); temp = temp->next; } printf ( "NULL" ); } /* Driver program to test above functions*/ int main() { struct Node* head = newNode(1); head->next = newNode(2); head->next->next = newNode(3); head->next->next->next = newNode(4); head->next->next->next->next = newNode(5); head->next->next->next->next->next = newNode(4); head->next->next->next->next->next->next = newNode(4); printf ( "Created Linked list: " ); display(head); deleteLast(&head, 4); // Pass the address of the head pointer printf ( "List after deletion of 4: " ); display(head); return 0; } |
JAVA
import java.io.*; // A linked list Node class Node { int data; Node next; Node( int data) { this .data = data; this .next = null ; } } class GFG{ // Function to delete the last occurrence static Node deleteLast(Node head, int x) { Node temp = head; Node ptr = null ; while (temp != null ) { // If found key, update if (temp.data == x) ptr = temp; temp = temp.next; } // If the last occurrence is the last node if (ptr != null && ptr.next == null ) { temp = head; while (temp.next != ptr) { temp = temp.next; } temp.next = null ; } // If it is not the last node if (ptr != null && ptr.next != null ) { ptr.data = ptr.next.data; temp = ptr.next; ptr.next = ptr.next.next; } return head; } // This function prints contents of linked list // starting from the given Node static void display(Node head) { Node temp = head; if (head == null ) { System.out.print( "NULL" ); return ; } while (temp != null ) { System.out.print( temp.data+ " --> " ); temp = temp.next; } System.out.print( "NULL" ); } // Driver code public static void main(String[] args) { Node head = new Node( 1 ); head.next = new Node( 2 ); head.next.next = new Node( 3 ); head.next.next.next = new Node( 4 ); head.next.next.next.next = new Node( 5 ); head.next.next.next.next.next = new Node( 4 ); head.next.next.next.next.next.next = new Node( 4 ); System.out.print( "Created Linked list: " ); display(head); // Pass the address of the head pointer head = deleteLast(head, 4 ); System.out.print( "List after deletion of 4: " ); display(head); } } // This code is contributed by patel2127 |
Python3
# A linked list Node class Node: def __init__( self , new_data): self .data = new_data self . next = None # Function to delete the last occurrence def deleteLast(head, x): temp = head ptr = None while (temp ! = None ): # If found key, update if (temp.data = = x): ptr = temp temp = temp. next # If the last occurrence is the last node if (ptr ! = None and ptr. next = = None ): temp = head while (temp. next ! = ptr): temp = temp. next temp. next = None # If it is not the last node if (ptr ! = None and ptr. next ! = None ): ptr.data = ptr. next .data temp = ptr. next ptr. next = ptr. next . next return head # Utility function to create a new node # with given key def newNode(x): node = Node( 0 ) node.data = x node. next = None return node # This function prints contents of linked # list starting from the given Node def display(head): temp = head if (head = = None ): print ( "NULL" ) return while (temp ! = None ): print ( temp.data, " --> " , end = "") temp = temp. next print ( "NULL" ) # Driver code head = newNode( 1 ) head. next = newNode( 2 ) head. next . next = newNode( 3 ) head. next . next . next = newNode( 4 ) head. next . next . next . next = newNode( 5 ) head. next . next . next . next . next = newNode( 4 ) head. next . next . next . next . next . next = newNode( 4 ) print ( "Created Linked list: " , end = '') display(head) # Pass the address of the head pointer head = deleteLast(head, 4 ) print ( "List after deletion of 4: " , end = '') display(head) # This code is contributed by rutvik_56 |
Javascript
<script> // A linked list Node class Node { // Utility function to create a new node // with given key constructor(data) { this .data = data; this .next = null ; } } // Function to delete the last occurrence function deleteLast(head, x) { let temp = head; let prt = null ; while (temp != null ) { //If found key, update if (temp.data == x) ptr = temp; temp = temp.next; } // If the last occurrence is the last node if (ptr != null && ptr.next == null ) { temp = head; while (temp.next != ptr) { temp = temp.next; } temp.next = null ; } // If it is not the last node if (ptr != null && ptr.next != null ) { ptr.data = ptr.next.data; temp = ptr.next; ptr.next = ptr.next.next; } return head; } // This function prints contents of linked // list starting from the given Node function display(head) { let temp = head if (head == null ) { document.write( "NULL<br>" ); return ; } while (temp != null ) { document.write( temp.data, " --> " , end = "" ); temp = temp.next; } document.write( "NULL<br>" ) } // Driver code let head = new Node(1) head.next = new Node(2) head.next.next = new Node(3) head.next.next.next = new Node(4) head.next.next.next.next = new Node(5) head.next.next.next.next.next = new Node(4) head.next.next.next.next.next.next = new Node(4); document.write( "Created Linked list: " ); display(head) // Pass the address of the head pointer head = deleteLast(head, 4) document.write( "List after deletion of 4: " ) display(head) // This code is contributed by avanitrachhadiya2155 </script> |
输出
Created Linked list: 1 --> 2 --> 3 --> 4 --> 5 --> 4 --> 4 --> NULLList after deletion of 4: 1 --> 2 --> 3 --> 4 --> 5 --> 4 --> NULL
给出一个喜欢的列表和一个要删除的密钥。从链接中删除上次出现的关键点。该列表可能有重复项。
例子 :
Input: 1->2->3->5->2->10, key = 2Output: 1->2->3->5->10
这个想法是从头到尾遍历链表。在遍历时，跟踪最后一次出现的关键点。遍历完整列表后，通过复制下一个节点的数据并删除下一个节点来删除最后一个引用。
C++
// A C++ program to demonstrate deletion of last // Node in singly linked list #include <bits/stdc++.h> // A linked list Node struct Node { int key; struct Node* next; }; void deleteLast(Node* head, int key) { // Initialize previous of Node to be deleted Node* x = NULL; // Start from head and find the Node to be // deleted Node* temp = head; while (temp) { // If we found the key, update xv if (temp->key == key) x = temp; temp = temp->next; } // key occurs at-least once if (x != NULL) { // Copy key of next Node to x x->key = x->next->key; // Store and unlink next temp = x->next; x->next = x->next->next; // Free memory for next delete temp; } } /* Utility function to create a new node with given key */ Node* newNode( int key) { Node* temp = new Node; temp->key = key; temp->next = NULL; return temp; } // This function prints contents of linked list // starting from the given Node void printList( struct Node* node) { while (node != NULL) { printf ( " %d " , node->key); node = node->next; } } /* Driver program to test above functions*/ int main() { /* Start with the empty list */ struct Node* head = newNode(1); head->next = newNode(2); head->next->next = newNode(3); head->next->next->next = newNode(5); head->next->next->next->next = newNode(2); head->next->next->next->next->next = newNode(10); puts ( "Created Linked List: " ); printList(head); deleteLast(head, 2); puts ( "Linked List after Deletion of 1: " ); printList(head); return 0; } |
JAVA
// A Java program to demonstrate deletion of last // Node in singly linked list class GFG { // A linked list Node static class Node { int key; Node next; }; static Node deleteLast(Node head, int key) { // Initialize previous of Node to be deleted Node x = null ; // Start from head and find the Node to be // deleted Node temp = head; while (temp != null ) { // If we found the key, update xv if (temp.key == key) x = temp; temp = temp.next; } // key occurs at-least once if (x != null ) { // Copy key of next Node to x x.key = x.next.key; // Store and unlink next temp = x.next; x.next = x.next.next; // Free memory for next } return head; } /// Utility function to create a new node with //given key / static Node newNode( int key) { Node temp = new Node(); temp.key = key; temp.next = null ; return temp; } // This function prints contents of linked list // starting from the given Node static void printList( Node node) { while (node != null ) { System.out.printf( " %d " , node.key); node = node.next; } } // Driver code/ public static void main(String args[]) { // /Start with the empty list / Node head = newNode( 1 ); head.next = newNode( 2 ); head.next.next = newNode( 3 ); head.next.next.next = newNode( 5 ); head.next.next.next.next = newNode( 2 ); head.next.next.next.next.next = newNode( 10 ); System.out.printf( "Created Linked List: " ); printList(head); deleteLast(head, 2 ); System.out.printf( "Linked List after Deletion of 1: " ); printList(head); } } // This code is contributed by Arnab Kundu |
Python3
# Python3 program to demonstrate deletion of # last Node in singly linked list # A linked list Node class Node: # Constructor to initialize the node object def __init__( self , data): self .data = data self . next = None def deleteLast(head, key) : # Initialize previous of Node to be deleted x = None # Start from head and find the Node to be # deleted temp = head while (temp ! = None ) : # If we found the key, update xv if (temp.key = = key) : x = temp temp = temp. next # key occurs at-least once if (x ! = None ) : # Copy key of next Node to x x.key = x. next .key # Store and unlink next temp = x. next x. next = x. next . next # Free memory for next return head # Utility function to create # a new node with given key def newNode(key) : temp = Node( 0 ) temp.key = key temp. next = None return temp # This function prints contents of linked list # starting from the given Node def printList( node) : while (node ! = None ) : print ( node.key, end = " " ) node = node. next # Driver Code if __name__ = = '__main__' : # Start with the empty list head = newNode( 1 ) head. next = newNode( 2 ) head. next . next = newNode( 3 ) head. next . next . next = newNode( 5 ) head. next . next . next . next = newNode( 2 ) head. next . next . next . next . next = newNode( 10 ) print ( "Created Linked List: " ) printList(head) deleteLast(head, 2 ) print ( "Linked List after Deletion of 1: " ) printList(head) # This code is contributed by Arnab Kundu |
C#
// C# program to demonstrate deletion of last // Node in singly linked list using System; class GFG { // A linked list Node public class Node { public int key; public Node next; }; static Node deleteLast(Node head, int key) { // Initialize previous of Node to be deleted Node x = null ; // Start from head and find the Node to be // deleted Node temp = head; while (temp != null ) { // If we found the key, update xv if (temp.key == key) x = temp; temp = temp.next; } // key occurs at-least once if (x != null ) { // Copy key of next Node to x x.key = x.next.key; // Store and unlink next temp = x.next; x.next = x.next.next; // Free memory for next } return head; } /// Utility function to create a new node with //given key / static Node newNode( int key) { Node temp = new Node(); temp.key = key; temp.next = null ; return temp; } // This function prints contents of linked list // starting from the given Node static void printList( Node node) { while (node != null ) { Console.Write( " {0} " , node.key); node = node.next; } } // Driver code public static void Main(String []args) { // Start with the empty list Node head = newNode(1); head.next = newNode(2); head.next.next = newNode(3); head.next.next.next = newNode(5); head.next.next.next.next = newNode(2); head.next.next.next.next.next = newNode(10); Console.Write( "Created Linked List: " ); printList(head); deleteLast(head, 2); Console.Write( "Linked List after Deletion of 1: " ); printList(head); } } // This code has been contributed by 29AjayKumar |
Javascript
<script> // A Javascript program to demonstrate // deletion of last Node in singly // linked list class Node { constructor(key) { this .key = key; this .next = null ; } } function deleteLast(head, key) { // Initialize previous of Node to be deleted let x = null ; // Start from head and find the Node to be // deleted let temp = head; while (temp != null ) { // If we found the key, update xv if (temp.key == key) x = temp; temp = temp.next; } // key occurs at-least once if (x != null ) { // Copy key of next Node to x x.key = x.next.key; // Store and unlink next temp = x.next; x.next = x.next.next; // Free memory for next } return head; } // This function prints contents of linked // list starting from the given Node function printList(node) { while (node != null ) { document.write(node.key + " " ); node = node.next; } } // Driver code let head = new Node(1); head.next = new Node(2); head.next.next = new Node(3); head.next.next.next = new Node(5); head.next.next.next.next = new Node(2); head.next.next.next.next.next = new Node(10); document.write( "Created Linked List: <br>" ); printList(head); deleteLast(head, 2); document.write( "<br>Linked List after " + "Deletion of 1: <br>" ); printList(head); // This code is contributed by rag2127 </script> |
输出：
Created Linked List: 1 2 3 5 2 10 Linked List after Deletion of 1: 1 2 3 5 10
当要删除的节点是最后一个节点时，上述解决方案不起作用。 以下解决方案处理所有情况。
C++
// A C++ program to demonstrate deletion of last // Node in singly linked list #include <bits/stdc++.h> using namespace std; // A linked list Node struct Node { int data; struct Node* next; }; // Function to delete the last occurrence void deleteLast( struct Node* head, int x) { struct Node *temp = head, *ptr = NULL; while (temp) { // If found key, update if (temp->data == x) ptr = temp; temp = temp->next; } // If the last occurrence is the last node if (ptr != NULL && ptr->next == NULL) { temp = head; while (temp->next != ptr) temp = temp->next; temp->next = NULL; } // If it is not the last node if (ptr != NULL && ptr->next != NULL) { ptr->data = ptr->next->data; temp = ptr->next; ptr->next = ptr->next->next; free (temp); } } /* Utility function to create a new node with given key */ struct Node* newNode( int x) { Node* node = new Node ; node->data = x; node->next = NULL; return node; } // This function prints contents of linked list // starting from the given Node void display( struct Node* head) { struct Node* temp = head; if (head == NULL) { cout << "NULL" ; return ; } while (temp != NULL) { cout << " --> " << temp->data; temp = temp->next; } cout << "NULL" ; } /* Driver program to test above functions*/ int main() { struct Node* head = newNode(1); head->next = newNode(2); head->next->next = newNode(3); head->next->next->next = newNode(4); head->next->next->next->next = newNode(5); head->next->next->next->next->next = newNode(4); head->next->next->next->next->next->next = newNode(4); cout << "Created Linked list: " ; display(head); deleteLast(head, 4); cout << "List after deletion of 4: " ; display(head); return 0; } // This code is contributed by shivanisinghss2110 |
C
// A C program to demonstrate deletion of last // Node in singly linked list #include <stdio.h> #include <stdlib.h> // A linked list Node struct Node { int data; struct Node* next; }; // Function to delete the last occurrence void deleteLast( struct Node* head, int x) { struct Node *temp = head, *ptr = NULL; while (temp) { // If found key, update if (temp->data == x) ptr = temp; temp = temp->next; } // If the last occurrence is the last node if (ptr != NULL && ptr->next == NULL) { temp = head; while (temp->next != ptr) temp = temp->next; temp->next = NULL; } // If it is not the last node if (ptr != NULL && ptr->next != NULL) { ptr->data = ptr->next->data; temp = ptr->next; ptr->next = ptr->next->next; free (temp); } } /* Utility function to create a new node with given key */ struct Node* newNode( int x) { struct Node* node = malloc ( sizeof ( struct Node*)); node->data = x; node->next = NULL; return node; } // This function prints contents of linked list // starting from the given Node void display( struct Node* head) { struct Node* temp = head; if (head == NULL) { printf ( "NULL" ); return ; } while (temp != NULL) { printf ( "%d --> " , temp->data); temp = temp->next; } printf ( "NULL" ); } /* Driver program to test above functions*/ int main() { struct Node* head = newNode(1); head->next = newNode(2); head->next->next = newNode(3); head->next->next->next = newNode(4); head->next->next->next->next = newNode(5); head->next->next->next->next->next = newNode(4); head->next->next->next->next->next->next = newNode(4); printf ( "Created Linked list: " ); display(head); deleteLast(head, 4); printf ( "List after deletion of 4: " ); display(head); return 0; } |
JAVA
// Java program to demonstrate deletion of last // Node in singly linked list class GFG { // A linked list Node static class Node { int data; Node next; }; // Function to delete the last occurrence static void deleteLast(Node head, int x) { Node temp = head, ptr = null ; while (temp!= null ) { // If found key, update if (temp.data == x) ptr = temp; temp = temp.next; } // If the last occurrence is the last node if (ptr != null && ptr.next == null ) { temp = head; while (temp.next != ptr) temp = temp.next; temp.next = null ; } // If it is not the last node if (ptr != null && ptr.next != null ) { ptr.data = ptr.next.data; temp = ptr.next; ptr.next = ptr.next.next; System.gc(); } } /* Utility function to create a new node with given key */ static Node newNode( int x) { Node node = new Node(); node.data = x; node.next = null ; return node; } // This function prints contents of linked list // starting from the given Node static void display(Node head) { Node temp = head; if (head == null ) { System.out.print( "null" ); return ; } while (temp != null ) { System.out.printf( "%d --> " , temp.data); temp = temp.next; } System.out.print( "null" ); } /* Driver code*/ public static void main(String[] args) { Node head = newNode( 1 ); head.next = newNode( 2 ); head.next.next = newNode( 3 ); head.next.next.next = newNode( 4 ); head.next.next.next.next = newNode( 5 ); head.next.next.next.next.next = newNode( 4 ); head.next.next.next.next.next.next = newNode( 4 ); System.out.print( "Created Linked list: " ); display(head); deleteLast(head, 4 ); System.out.print( "List after deletion of 4: " ); display(head); } } /* This code is contributed by PrinciRaj1992 */ |
Python3
# A Python3 program to demonstrate deletion of last # Node in singly linked list # A linked list Node class Node: def __init__( self , new_data): self .data = new_data self . next = None # Function to delete the last occurrence def deleteLast(head, x): temp = head ptr = None while (temp! = None ): # If found key, update if (temp.data = = x) : ptr = temp temp = temp. next # If the last occurrence is the last node if (ptr ! = None and ptr. next = = None ): temp = head while (temp. next ! = ptr) : temp = temp. next temp. next = None # If it is not the last node if (ptr ! = None and ptr. next ! = None ): ptr.data = ptr. next .data temp = ptr. next ptr. next = ptr. next . next return head # Utility function to create a new node with # given key def newNode(x): node = Node( 0 ) node.data = x node. next = None return node # This function prints contents of linked list # starting from the given Node def display( head): temp = head if (head = = None ): print ( "None" ) return while (temp ! = None ): print ( temp.data, " -> " ,end = "") temp = temp. next print ( "None" ) # Driver code head = newNode( 1 ) head. next = newNode( 2 ) head. next . next = newNode( 3 ) head. next . next . next = newNode( 4 ) head. next . next . next . next = newNode( 5 ) head. next . next . next . next . next = newNode( 4 ) head. next . next . next . next . next . next = newNode( 4 ) print ( "Created Linked list: " ) display(head) head = deleteLast(head, 4 ) print ( "List after deletion of 4: " ) display(head) # This code is contributed by Arnab Kundu |
C#
// C# program to demonstrate deletion of last // Node in singly linked list using System; class GFG { // A linked list Node public class Node { public int data; public Node next; }; // Function to delete the last occurrence static void deleteLast(Node head, int x) { Node temp = head, ptr = null ; while (temp != null ) { // If found key, update if (temp.data == x) ptr = temp; temp = temp.next; } // If the last occurrence is the last node if (ptr != null && ptr.next == null ) { temp = head; while (temp.next != ptr) temp = temp.next; temp.next = null ; } // If it is not the last node if (ptr != null && ptr.next != null ) { ptr.data = ptr.next.data; temp = ptr.next; ptr.next = ptr.next.next; } } /* Utility function to create a new node with given key */ static Node newNode( int x) { Node node = new Node(); node.data = x; node.next = null ; return node; } // This function prints contents of linked list // starting from the given Node static void display(Node head) { Node temp = head; if (head == null ) { Console.Write( "null" ); return ; } while (temp != null ) { Console.Write( "{0} --> " , temp.data); temp = temp.next; } Console.Write( "null" ); } /* Driver code*/ public static void Main(String[] args) { Node head = newNode(1); head.next = newNode(2); head.next.next = newNode(3); head.next.next.next = newNode(4); head.next.next.next.next = newNode(5); head.next.next.next.next.next = newNode(4); head.next.next.next.next.next.next = newNode(4); Console.Write( "Created Linked list: " ); display(head); deleteLast(head, 4); Console.Write( "List after deletion of 4: " ); display(head); } } // This code contributed by Rajput-Ji |
Javascript
<script> // JavaScript program to demonstrate // deletion of last // Node in singly linked list // A linked list Node class Node { constructor() { this .data = 0; this .next = null ; } } // Function to delete the last occurrence function deleteLast(head , x) { var temp = head, ptr = null ; while (temp != null ) { // If found key, update if (temp.data == x) ptr = temp; temp = temp.next; } // If the last occurrence is the last node if (ptr != null && ptr.next == null ) { temp = head; while (temp.next != ptr) temp = temp.next; temp.next = null ; } // If it is not the last node if (ptr != null && ptr.next != null ) { ptr.data = ptr.next.data; temp = ptr.next; ptr.next = ptr.next.next; } } /* Utility function to create a new node with given key */ function newNode(x) { var node = new Node(); node.data = x; node.next = null ; return node; } // This function prints contents of linked list // starting from the given Node function display(head) { var temp = head; if (head == null ) { document.write( "null<br/>" ); return ; } while (temp != null ) { document.write( temp.data + " --> " ); temp = temp.next; } document.write( "null<br/>" ); } /* Driver code */ var head = newNode(1); head.next = newNode(2); head.next.next = newNode(3); head.next.next.next = newNode(4); head.next.next.next.next = newNode(5); head.next.next.next.next.next = newNode(4); head.next.next.next.next.next.next = newNode(4); document.write( "Created Linked list: " ); display(head); deleteLast(head, 4); document.write( "List after deletion of 4: " ); display(head); // This code contributed by gauravrajput1 </script> |
输出：
Created Linked List: 1 2 3 4 5 4 4 Linked List after Deletion of 1: 1 2 3 4 5 4
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