给定一个包含N个节点的单链接列表，任务是从列表中删除所有偶数节点。
例子：
Input: LL = 1 -> 4 -> 3 -> 18 -> 19
Output: 1 -> 3 -> 19
Input: LL = 5 -> 3 -> 6 -> 8 -> 4 -> 1 -> 2 -> 9
Output: 5 -> 3 -> 1 -> 9
方法：
- 这个想法是一个遍历单个链接列表的节点，并获得具有偶数数据的节点的指针。按照本文中使用的方法删除那些节点。
下面是上述想法的实现：
C++
// C++ implementation to delete all
// even nodes from the singly linked list
#include
using namespace std;
// Node of the singly linked list
struct Node
{
int data;
struct Node* next;
};
// Function to insert a node at
// the beginning of the singly
// Linked 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;
}
// Function to delete a node in a
// singly Linked List.
// head_ref --> Pointer to head
// node pointer.
// key --> Node to be deleted
void deleteNode(struct Node** head_ref,
int key)
{
// Store head node
struct Node *temp = *head_ref,
*prev;
// If head node itself holds
// the key to be deleted
if (temp != NULL
&& temp->data == key) {
// Changed head
*head_ref = temp->next;
// Free old head
free(temp);
return;
}
// 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 memory
free(temp);
}
// Function to delete all the
// even nodes from the
// singly linked list
void deleteEvenNodes(Node** head_ref)
{
Node* ptr = *head_ref;
// Node* next;
while (ptr != NULL) {
// next = ptr->next;
// If true, delete node 'ptr'
if (ptr->data % 2 == 0)
deleteNode(head_ref,
ptr->data);
ptr = ptr->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
Node* head = NULL;
push(&head, 19);
push(&head, 18);
push(&head, 3);
push(&head, 4);
push(&head, 1);
printf("Initial List: ");
printList(head);
deleteEvenNodes(&head);
printf("\nFinal List: ");
printList(head);
} Java
// Java implementation to delete all
// even nodes from the singly linked list
class LinkedList{
// head of list
Node head;
// Linked list Node
class Node
{
int data;
Node next;
Node(int d)
{
data = d;
next = null;
}
}
// Function to insert a node at
// the beginning of the singly
// Linked List
public void push(int new_data)
{
Node new_node = new Node(new_data);
new_node.next = head;
head = new_node;
}
// Function to delete a node in a
// singly Linked List.
void deleteNode(int key)
{
// Store head node
Node temp = head, prev = null;
// If head node itself holds the
// key to be deleted
if (temp != null && temp.data == key)
{
// Changed head
head = temp.next;
return;
}
// Search for the key to be deleted,
// keep track of the previous node
// as we need to change temp.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;
}
// Function to delete all the nodes
// from linked list containing
// even numbers.
void deleteEvenNodes()
{
Node ptr = head;
// loop to iterate the linked list
while(ptr != null)
{
// If containing element is even
if(ptr.data % 2 == 0)
{
// Delete the node
deleteNode(ptr.data);
}
ptr = ptr.next;
}
}
// This function prints contents of linked
// list starting from the given node
public void printList()
{
Node ptr = head;
while (ptr != null)
{
System.out.print(ptr.data + "-> ");
ptr = ptr.next;
}
}
// Driver code
public static void main(String[] args)
{
LinkedList head = new LinkedList();
head.push(19);
head.push(18);
head.push(3);
head.push(4);
head.push(1);
System.out.print("\nInitial List: ");
head.printList();
head.deleteEvenNodes();
System.out.print("\nFinal List: ");
head.printList();
}
}
// This code is contributed by Amit MangalPython3
# Python3 implementation to delete all
# even nodes from the singly linked list
# Node class
class Node:
# Function to initialize the node object
def __init__(self, data):
# Assign data
self.data = data
# Initialize
# next as null
self.next = None
# Linked List Class
class LinkedList:
# Function to initialize the
# LinkedList class.
def __init__(self):
# Initialize head as None
self.head = None
# This function insert a new node at
# the beginning of the linked list
def push(self, new_data):
# Create a new Node
new_node = Node(new_data)
# Make next of new Node as head
new_node.next = self.head
# Move the head to point to new Node
self.head = new_node
# Method to print the linked list
def printList(self):
# Object to iterate
# the list
ptr = self.head
# Loop to iterate list
while(ptr != None):
print(ptr.data, '-> ', end = '')
# Moving the iterating object
# to next node
ptr = ptr.next
print()
# Method to delete a node in
# a singly linked list.
def deleteNode(self, key):
temp = self.head
# If head node itself holds
# the key to be deleted.
if(temp != None and temp.data == key):
# Changing head of list.
self.head = temp.next
return
# 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 is not present in list
if(temp == None):
return
# Unlink the node from
# linked list
prev.next = temp.next
# Method to delete all the
# even nodes from singly
# linked list.
def deleteEvenNodes(self):
ptr = self.head
# Loop to iterate the
# linked list.
while(ptr != None):
# If node contains even number.
if(ptr.data % 2 == 0):
# Deleting the node
self.deleteNode(ptr.data)
ptr = ptr.next
# Driver code
if __name__=='__main__':
head = LinkedList()
# Pushing elements at start
# of linked list.
head.push(19)
head.push(18)
head.push(3)
head.push(4)
head.push(1)
# Print initial linked list
print("Initial list: ", end = '')
head.printList()
# Calling the function to delete
# nodes containing even numbers.
head.deleteEvenNodes()
# Print the final list
print("Final list: ", end = '')
head.printList()
# This code is contributed by Amit MangalC#
// C# implementation to delete all
// even nodes from the singly linked list
using System;
class List{
// head of list
Node head;
// Linked list Node
public class Node
{
public int data;
public Node next;
public Node(int d)
{
data = d;
next = null;
}
}
// Function to insert a node at
// the beginning of the singly
// Linked List
public void push(int new_data)
{
Node new_node = new Node(new_data);
new_node.next = head;
head = new_node;
}
// Function to delete a node in a
// singly Linked List.
void deleteNode(int key)
{
// Store head node
Node temp = head, prev = null;
// If head node itself holds the
// key to be deleted
if (temp != null &&
temp.data == key)
{
// Changed head
head = temp.next;
return;
}
// Search for the key to be deleted,
// keep track of the previous node
// as we need to change temp.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;
}
// Function to delete
// all the nodes from
// linked list containing
// even numbers.
void deleteEvenNodes()
{
Node ptr = head;
// loop to iterate the linked list
while(ptr != null)
{
// If containing element is even
if(ptr.data % 2 == 0)
{
// Delete the node
deleteNode(ptr.data);
}
ptr = ptr.next;
}
}
// This function prints contents of linked
// list starting from the given node
public void printList()
{
Node ptr = head;
while (ptr != null)
{
Console.Write(ptr.data + "-> ");
ptr = ptr.next;
}
}
// Driver code
public static void Main(String []args)
{
List head = new List();
head.push(19);
head.push(18);
head.push(3);
head.push(4);
head.push(1);
Console.Write("\nInitial List: ");
head.printList();
head.deleteEvenNodes();
Console.Write("\nFinal List: ");
head.printList();
}
}
// This code contributed by gauravrajput1输出：
Initial List: 1 -> 4 -> 3 -> 18 -> 19 ->
Final List: 1 -> 3 -> 19 ->
时间复杂度： O(N) ，其中N是节点总数。