删除链表中所有出现的给定键
原文：https://www.geeksforgeeks.org/delete-occurrences-given-key-linked-list/
给定一个单链表，请删除其中所有出现的给定键。 例如，考虑以下列表。
示例：
Input: 2 -> 2 -> 1 -> 8 -> 2 -> 3 -> 2 -> 7
Key to delete = 2
Output: 1 -> 8 -> 3 -> 7
这主要是此帖子（删除给定键的首次出现）。
我们需要首先检查头节点上的所有事件，并适当地更改头节点。 然后，我们需要检查循环中所有出现的事件，并将它们一一删除。](http://quiz.geeksforgeeks.org/linked-list-set-3-deleting-node/)
以下是上述想法的实现：
C++
// C++ program to delete all occurrences
// of a given key in linked list
#include <bits/stdc++.h>
using namespace std;
// A linked list node
class Node
{
public:
int data;
Node* next;
};
// Given a reference (pointer) to the head
// of a list and an int, inserts a new node
// on the front of the list
Node* push(Node* head, int new_data)
{
Node* new_node = new Node();
new_node->data = new_data;
new_node->next = head;
head = new_node;
return head;
}
// Given a reference (pointer)to the head
// of a list and a key, deletes all
// occurrence of the given key in
// linked list
Node* deleteKey(Node *head,int x)
{
// Store head node
Node *tmp = head;
while (head->data == x)
{
head = head->next;
}
while (tmp->next != NULL)
{
if (tmp->next->data == x)
{
tmp->next = tmp->next->next;
}
else
{
tmp = tmp->next;
}
}
return head;
}
// This function prints contents of
// linked list starting from the
// given node
void printList(Node* node)
{
while (node->next != NULL)
{
cout << node->data << " ";
node = node->next;
}
cout << node->data;
}
// Driver code
int main()
{
// Start with the empty list
Node* head = NULL;
head = push(head, 7);
head = push(head, 2);
head = push(head, 3);
head = push(head, 2);
head = push(head, 8);
head = push(head, 1);
head = push(head, 2);
head = push(head, 2);
// Key to delete
int key = 2 ;
cout << "Created Linked List:\n ";
printList(head);
// Function call
head = deleteKey(head, key);
cout << "\nLinked List after Deletion is:\n";
printList(head);
return 0;
}
// This code is contributed by shivamsharma2020
C
// C Program to delete all occurrences of a given key in
// linked list
#include <stdio.h>
#include <stdlib.h>
// A linked list node
struct Node
{
int data;
struct Node* next;
};
/* Given a reference (pointer to pointer) to the head of a
list and an int, inserts a new node on the front of the
list. */
void push(struct Node** head_ref, int new_data)
{
struct Node* new_node
= (struct Node*)malloc(sizeof(struct Node));
new_node->data = new_data;
new_node->next = (*head_ref);
(*head_ref) = new_node;
}
/* Given a reference (pointer to pointer) to the head of a
list and a key, deletes all occurrence of the given key
in linked list */
void deleteKey(struct Node** head_ref, int key)
{
// Store head node
struct Node *temp = *head_ref, *prev;
// If head node itself holds the key or multiple
// occurrences of key
while (temp != NULL && temp->data == key)
{
*head_ref = temp->next; // Changed head
free(temp); // free old head
temp = *head_ref; // Change Temp
}
// Delete occurrences other than head
while (temp != NULL)
{
// Search for the key to be deleted, keep track of
// the previous node as we need to change
// 'prev->next'
while (temp != NULL && temp->data != key)
{
prev = temp;
temp = temp->next;
}
// If key was not present in linked list
if (temp == NULL)
return;
// Unlink the node from linked list
prev->next = temp->next;
free(temp); // Free memory
// Update Temp for next iteration of outer loop
temp = prev->next;
}
}
// This function prints contents of linked list starting
// from the given node
void printList(struct Node* node)
{
while (node != NULL)
{
printf(" %d ", node->data);
node = node->next;
}
}
// Driver code
int main()
{
// Start with the empty list
struct Node* head = NULL;
push(&head, 7);
push(&head, 2);
push(&head, 3);
push(&head, 2);
push(&head, 8);
push(&head, 1);
push(&head, 2);
push(&head, 2);
int key = 2; // key to delete
puts("Created Linked List: ");
printList(head);
// Function call
deleteKey(&head, key);
puts("\nLinked List after Deletion is:");
printList(head);
return 0;
}
Java
// Java Program to delete all occurrences
// of a given key in linked list
class LinkedList
{
static Node head; // head of list
/* Linked list Node*/
class Node
{
int data;
Node next;
Node(int d)
{
data = d;
next = null;
}
}
/* Given a key, deletes all occurrence
of the given key in linked list */
void deleteKey(int key)
{
// Store head node
Node temp = head, prev = null;
// If head node itself holds the key
// or multiple occurrences of key
while (temp != null && temp.data == key)
{
head = temp.next; // Changed head
temp = head; // Change Temp
}
// Delete occurrences other than head
while (temp != null)
{
// Search for the key to be deleted,
// keep track of the previous node
// as we need to change 'prev->next'
while (temp != null && temp.data != key)
{
prev = temp;
temp = temp.next;
}
// If key was not present in linked list
if (temp == null)
return;
// Unlink the node from linked list
prev.next = temp.next;
// Update Temp for next iteration of outer loop
temp = prev.next;
}
}
/* Inserts a new Node at front of the list. */
public void push(int new_data)
{
Node new_node = new Node(new_data);
new_node.next = head;
head = new_node;
}
/* This function prints contents of linked list
starting from the given node */
public void printList()
{
Node tnode = head;
while (tnode != null)
{
System.out.print(tnode.data + " ");
tnode = tnode.next;
}
}
// Driver Code
public static void main(String[] args)
{
LinkedList llist = new LinkedList();
llist.push(7);
llist.push(2);
llist.push(3);
llist.push(2);
llist.push(8);
llist.push(1);
llist.push(2);
llist.push(2);
int key = 2; // key to delete
System.out.println("Created Linked list is:");
llist.printList();
// Function call
llist.deleteKey(key);
System.out.println(
"\nLinked List after Deletion is:");
llist.printList();
}
}
// This code is contributed by Shubham
Python3
# Python3 program to delete all occurrences
# of a given key in linked list
# Link list node
class Node:
def __init__(self, data):
self.data = data
self.next = None
# Given a reference (pointer to pointer)
# to the head of a list and an int,
# inserts a new node on the front of the list.
def push(head_ref, new_data):
new_node = Node(0)
new_node.data = new_data
new_node.next = (head_ref)
(head_ref) = new_node
return head_ref
# Given a reference (pointer to pointer)
# to the head of a list and a key,
# deletes all occurrence of the given key
# in linked list
def deleteKey(head_ref, key):
# Store head node
temp = head_ref
prev = None
# If head node itself holds the key
# or multiple occurrences of key
while (temp != None and temp.data == key):
head_ref = temp.next # Changed head
temp = head_ref # Change Temp
# Delete occurrences other than head
while (temp != None):
# Search for the key to be deleted,
# keep track of the previous node
# as we need to change 'prev.next'
while (temp != None and temp.data != key):
prev = temp
temp = temp.next
# If key was not present in linked list
if (temp == None):
return head_ref
# Unlink the node from linked list
prev.next = temp.next
# Update Temp for next iteration of outer loop
temp = prev.next
return head_ref
# This function prints contents of linked list
# starting from the given node
def printList(node):
while (node != None):
print(node.data, end=" ")
node = node.next
# Driver Code
if __name__ == '__main__':
# Start with the empty list
head = None
head = push(head, 7)
head = push(head, 2)
head = push(head, 3)
head = push(head, 2)
head = push(head, 8)
head = push(head, 1)
head = push(head, 2)
head = push(head, 2)
key = 2 # key to delete
print("Created Linked List: ")
printList(head)
# Function call
head = deleteKey(head, key)
print("\nLinked List after Deletion is: ")
printList(head)
# This code is contributed by Arnab Kundu
C
// C# Program to delete all occurrences
// of a given key in linked list
using System;
class GFG
{
static Node head; // head of list
/* Linked list Node*/
public class Node
{
public int data;
public Node next;
public Node(int d)
{
data = d;
next = null;
}
}
/* Given a key, deletes all occurrence
of the given key in linked list */
void deleteKey(int key)
{
// Store head node
Node temp = head, prev = null;
// If head node itself holds the key
// or multiple occurrences of key
while (temp != null && temp.data == key)
{
head = temp.next; // Changed head
temp = head; // Change Temp
}
// Delete occurrences other than head
while (temp != null)
{
// Search for the key to be deleted,
// keep track of the previous node
// as we need to change 'prev->next'
while (temp != null && temp.data != key)
{
prev = temp;
temp = temp.next;
}
// If key was not present in linked list
if (temp == null)
return;
// Unlink the node from linked list
prev.next = temp.next;
// Update Temp for next iteration of outer loop
temp = prev.next;
}
}
/* Inserts a new Node at front of the list. */
public void Push(int new_data)
{
Node new_node = new Node(new_data);
new_node.next = head;
head = new_node;
}
/* This function prints contents of linked list
starting from the given node */
public void printList()
{
Node tnode = head;
while (tnode != null)
{
Console.Write(tnode.data + " ");
tnode = tnode.next;
}
}
// Driver Code
public static void Main(String[] args)
{
GFG llist = new GFG();
llist.Push(7);
llist.Push(2);
llist.Push(3);
llist.Push(2);
llist.Push(8);
llist.Push(1);
llist.Push(2);
llist.Push(2);
int key = 2; // key to delete
Console.WriteLine("Created Linked list is:");
llist.printList();
// Function call
llist.deleteKey(key);
Console.WriteLine(
"\nLinked List after Deletion is:");
llist.printList();
}
}
// This code is contributed by 29AjayKumar
输出：
Created Linked List:
2 2 1 8 2 3 2 7
Linked List after Deletion is:
1 8 3 7
本文由 Saransh 提供。 如果发现任何不正确的地方，或者您想分享有关上述主题的更多信息，请发表评论。
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