Given a singly linked list, the task is to remove the vowels from the given linked list.
Examples:
Input: g -> e -> e -> k -> s -> f -> o -> r -> g -> e -> e -> k -> s
Output: g -> k -> s -> f -> r -> g -> k -> s
Explanation:
After removing vowels {e, e}, {o}, {e, e}. The linked list becomes
g -> k -> s -> f -> r -> g -> k -> sInput: a -> a -> a -> g -> e -> e -> k -> s -> i -> i -> i -> m
Output: g -> k -> s -> m
Explanation:
After removing vowels {a, a, a}, {e, e}, {i, i, i}. The linked list becomes
g -> k -> s -> f -> r -> g -> k -> s
Approach:
There are three cases where we can find the vowels in the given linked list:
-
At the starting of the linked list: For removing vowels from the start of the linked list, move the head Node to the first consonant that occurs in the linked list.
For Example:
For Linked List: a -> e -> i -> a -> c -> r -> d -> NULL After moving the head Node from Node a to Node c, We have c -> r -> d -> NULL
-
In the between of the linked list: For removing vowels from the between of the linked list, the idea is to keep a marker of the last consonant found in the linked list before the vowel Nodes and change the next link of that Node with the next consonant Node found in the linked list after vowel Nodes.
For Example:
For Linked List:
c -> r -> d -> a -> e -> i -> a -> c -> r -> z -> NULL
last consonant before vowels {a, e, i, a} is d
and next consonant after vowels {a, e, i, a} is r
After linking next pointer of Node d to Node r, We have
c -> r -> d -> r -> z -> NULL-
At the end of the linked list: For removing vowels from the end of the linked list, the idea is to keep a marker of the last consonant found in the linked list before the vowel Nodes and change the next link of that Node with NULL.
For Example:
For Linked List:
c -> r -> d -> a -> e -> i -> a -> NULL
last consonant before vowels {a, e, i, a} is d
After changing the next link of Node to NULL, We have
c -> r -> d -> NULLBelow is the implementation of the above approach:
C++
// C++ program to remove vowels// Nodes in a linked list#include <bits/stdc++.h>using namespace std;
// A linked list nodestruct Node {
char data;
struct Node* next;
};// Head Nodestruct Node* head;
// Function to add new node to the// ListNode* newNode(char key)
{ Node* temp = new Node;
temp->data = key;
temp->next = NULL;
return temp;
}// Utility function to print the// linked listvoid printlist(Node* head)
{ if (!head) {
cout << "Empty List\n";
return;
}
while (head != NULL) {
cout << head->data << " ";
if (head->next)
cout << "-> ";
head = head->next;
}
cout << endl;
}// Utility function for checking vowelbool isVowel(char x)
{ return (x == 'a' || x == 'e' || x == 'i'
|| x == 'o' || x == 'u' || x == 'A'
|| x == 'E' || x == 'I' || x == 'O'
|| x == 'U');
}// Function to remove the vowels Nodevoid removeVowels()
{ // Node pointing to head Node
struct Node* ptr = head;
// Case 1 : Remove the trailing
// vowels
while (ptr != NULL) {
// If current Node is a vowel
// node then move the pointer
// to next node
if (isVowel(ptr->data))
ptr = ptr->next;
// Else break if a consonant
// node is found
else
break;
}
// This prev node used to link
// prev consonant to next
// consonant after vowels
struct Node* prev = ptr;
// Head points to the first
// consonant of the linked list
head = ptr;
ptr = ptr->next;
// Case 2: If vowels found in
// between of the linked list
while (ptr != NULL) {
// If current node is vowel
if (isVowel(ptr->data)) {
// Move ptr to the next
// node
ptr = ptr->next;
// Check for vowels
// occurring continuously
while (ptr != NULL) {
// If ptr is a vowel
// move to next pointer
if (isVowel(ptr->data)) {
ptr = ptr->next;
}
// Else break if
// consonant found
else
break;
}
// Case 3: If we have ending
// vowels then link the prev
// consonant to NULL
if (ptr == NULL) {
prev->next = NULL;
break;
}
// Case 2: change the next
// link of prev to current
// consonant pointing to
// ptr
else {
prev->next = ptr;
}
}
// Move prev and ptr to next
// for next iteration
prev = prev->next;
ptr = ptr->next;
}
}// Driver codeint main()
{ // Initialise the Linked List
head = newNode('a');
head->next = newNode('b');
head->next->next = newNode('c');
head->next->next->next = newNode('e');
head->next->next->next->next = newNode('f');
head->next->next->next->next->next = newNode('g');
head->next->next->next->next->next->next = newNode('i');
head->next->next->next->next->next->next->next = newNode('o');
// Print the given Linked List
printf("Linked list before :\n");
printlist(head);
removeVowels();
// Print the Linked List after
// removing vowels
printf("Linked list after :\n");
printlist(head);
return 0;
} |
Java
// Java program to remove vowels// Nodes in a linked listimport java.io.*;
// A linked list nodeclass Node
{ char data;
Node next;
// Function to add new node to the
// List
Node(char item)
{
data = item;
next = null;
}
}class GFG
{ // Head Node
public static Node head;
// Utility function to print the
// linked list
static void printlist(Node head)
{
if(head == null)
{
System.out.println("Empty List");
}
while(head != null)
{
System.out.print(head.data + " ");
if(head.next != null)
{
System.out.print("-> ");
}
head = head.next;
}
System.out.println();
}
// Utility function for checking vowel
static boolean isVowel(char x)
{
return (x == 'a' || x == 'e' || x == 'i' ||
x == 'o' || x == 'u' || x == 'A' ||
x == 'E' || x == 'I' || x == 'O' || x == 'U');
}
// Function to remove the vowels Node
static void removeVowels()
{
// Node pointing to head Node
Node ptr = head;
// Case 1 : Remove the trailing
// vowels
while(ptr != null)
{
// If current Node is a vowel
// node then move the pointer
// to next node
if(isVowel(ptr.data))
{
ptr = ptr.next;
}
// Else break if a consonant
// node is found
else
{
break;
}
}
// This prev node used to link
// prev consonant to next
// consonant after vowels
Node prev = ptr;
// Head points to the first
// consonant of the linked list
head = ptr;
ptr = ptr.next;
// Case 2: If vowels found in
// between of the linked list
while(ptr != null)
{
// If current node is vowel
if(isVowel(ptr.data))
{
// Move ptr to the next
// node
ptr = ptr.next;
// Check for vowels
// occurring continuously
while(ptr != null)
{
// If ptr is a vowel
// move to next pointer
if(isVowel(ptr.data))
{
ptr = ptr.next;
}
// Else break if
// consonant found
else
{
break;
}
}
// Case 3: If we have ending
// vowels then link the prev
// consonant to NULL
if(ptr == null)
{
prev.next = null;
break;
}
// Case 2: change the next
// link of prev to current
// consonant pointing to
// ptr
else
{
prev.next = ptr;
}
}
// Move prev and ptr to next
// for next iteration
prev = prev.next;
ptr = ptr.next;
}
}
// Driver code
public static void main (String[] args)
{
// Initialise the Linked List
GFG tree = new GFG();
tree.head = new Node('a');
tree.head.next = new Node('b');
tree.head.next.next = new Node('c');
tree.head.next.next.next = new Node('e');
tree.head.next.next.next.next = new Node('f');
tree.head.next.next.next.next.next = new Node('g');
tree.head.next.next.next.next.next.next = new Node('i');
tree.head.next.next.next.next.next.next.next = new Node('o');
// Print the given Linked List
System.out.println("Linked list before :");
printlist(head);
removeVowels();
// Print the Linked List after
// removing vowels
System.out.println("Linked list after :");
printlist(head);
}
}// This code is contributed by avanitrachhadiya2155 |
Python3
# Python3 program to remove vowels# Nodes in a linked list# A linked list nodeclass Node:
def __init__(self, x):
self.data = x
self.next = None
# Head Nodehead = None
# Utility function to print the# linked listdef printlist(head):
if (not head):
print("Empty List")
return
while (head != None):
print(head.data, end = " ")
if (head.next):
print(end="-> ")
head = head.next
print()
# Utility function for checking voweldef isVowel(x):
return (x == 'a' or x == 'e' or x == 'i'
or x == 'o' or x == 'u' or x == 'A'
or x == 'E' or x == 'I' or x == 'O'
or x == 'U')
# Function to remove the vowels Nodedef removeVowels():
global head
# Node pointing to head Node
ptr = head
# Case 1 : Remove the trailing
# vowels
while (ptr != None):
# If current Node is a vowel
# node then move the pointer
# to next node
if (isVowel(ptr.data)):
ptr = ptr.next
# Else break if a consonant
# node is found
else:
break
# This prev node used to link
# prev consonant to next
# consonant after vowels
prev = ptr
# Head points to the first
# consonant of the linked list
head = ptr
ptr = ptr.next
# Case 2: If vowels found in
# between of the linked list
while (ptr != None):
# If current node is vowel
if (isVowel(ptr.data)):
# Move ptr to the next
# node
ptr = ptr.next
# Check for vowels
# occurring continuously
while (ptr != None):
# If ptr is a vowel
# move to next pointer
if (isVowel(ptr.data)):
ptr = ptr.next
# Else break if
# consonant found
else:
break
# Case 3: If we have ending
# vowels then link the prev
# consonant to NULL
if (ptr == None):
prev.next = None
break
# Case 2: change the next
# link of prev to current
# consonant pointing to
# ptr
else:
prev.next = ptr
# Move prev and ptr to next
# for next iteration
prev = prev.next
ptr = ptr.next
# Driver codeif __name__ == '__main__':
# Initialise the Linked List
head = Node('a')
head.next = Node('b')
head.next.next = Node('c')
head.next.next.next = Node('e')
head.next.next.next.next = Node('f')
head.next.next.next.next.next = Node('g')
head.next.next.next.next.next.next = Node('i')
head.next.next.next.next.next.next.next = Node('o')
# Print the given Linked List
print("Linked list before :")
printlist(head)
removeVowels()
# Print the Linked List after
# removing vowels
print("Linked list after :")
printlist(head)
# This code is contributed by mohit kumar 29
|
C#
// C# program to remove vowels// Nodes in a linked listusing System;
// A linked list nodeclass Node
{ public char data;
public Node next;
// Function to add new node to the
// List
public Node(char item)
{
data = item;
next = null;
}
}class GFG{
// Head Nodestatic Node head;
// Utility function to print the// linked liststatic void printlist(Node head)
{ if (head == null)
{
Console.WriteLine("Empty List");
}
while (head != null)
{
Console.Write(head.data + " ");
if (head.next != null)
{
Console.Write("-> ");
}
head = head.next;
}
Console.WriteLine();
}// Utility function for checking vowelstatic bool isVowel(char x)
{ return (x == 'a' || x == 'e' ||
x == 'i' || x == 'o' ||
x == 'u' || x == 'A' ||
x == 'E' || x == 'I' ||
x == 'O' || x == 'U');
}// Function to remove the vowels Nodestatic void removeVowels()
{ // Node pointing to head Node
Node ptr = head;
// Case 1 : Remove the trailing
// vowels
while (ptr != null)
{
// If current Node is a vowel
// node then move the pointer
// to next node
if (isVowel(ptr.data))
{
ptr = ptr.next;
}
// Else break if a consonant
// node is found
else
{
break;
}
}
// This prev node used to link
// prev consonant to next
// consonant after vowels
Node prev = ptr;
// Head points to the first
// consonant of the linked list
head = ptr;
ptr = ptr.next;
// Case 2: If vowels found in
// between of the linked list
while (ptr != null)
{
// If current node is vowel
if (isVowel(ptr.data))
{
// Move ptr to the next
// node
ptr = ptr.next;
// Check for vowels
// occurring continuously
while (ptr != null)
{
// If ptr is a vowel
// move to next pointer
if (isVowel(ptr.data))
{
ptr = ptr.next;
}
// Else break if
// consonant found
else
{
break;
}
}
// Case 3: If we have ending
// vowels then link the prev
// consonant to NULL
if (ptr == null)
{
prev.next = null;
break;
}
// Case 2: change the next
// link of prev to current
// consonant pointing to
// ptr
else
{
prev.next = ptr;
}
}
// Move prev and ptr to next
// for next iteration
prev = prev.next;
ptr = ptr.next;
}
}// Driver codestatic public void Main()
{ // Initialise the Linked List
GFG.head = new Node('a');
GFG.head.next = new Node('b');
GFG.head.next.next = new Node('c');
GFG.head.next.next.next = new Node('e');
GFG.head.next.next.next.next = new Node('f');
GFG.head.next.next.next.next.next = new Node('g');
GFG.head.next.next.next.next.next.next = new Node('i');
GFG.head.next.next.next.next.next.next.next = new Node('o');
// Print the given Linked List
Console.WriteLine("Linked list before :");
printlist(head);
removeVowels();
// Print the Linked List after
// removing vowels
Console.WriteLine("Linked list after :");
printlist(head);
}}// This code is contributed by rag2127 |
Javascript
<script>// javascript program to remove vowels// Nodes in a linked list// A linked list nodeclass Node { // Function to add new node to the
// List
constructor( item) {
this.data = item;
this.next = null;
}
} // Head Node
var head;
// Utility function to print the
// linked list
function printlist(head) {
if (head == null) {
document.write("Empty List");
}
while (head != null) {
document.write(head.data + " ");
if (head.next != null) {
document.write("-> ");
}
head = head.next;
}
document.write("<br/>");
}
// Utility function for checking vowel
function isVowel( x) {
return (x == 'a' || x == 'e' || x == 'i' || x == 'o'
|| x == 'u' || x == 'A' || x == 'E' || x == 'I'
|| x == 'O'|| x == 'U');
}
// Function to remove the vowels Node
function removeVowels() {
// Node pointing to head Node
var ptr = head;
// Case 1 : Remove the trailing
// vowels
while (ptr != null) {
// If current Node is a vowel
// node then move the pointer
// to next node
if (isVowel(ptr.data)) {
ptr = ptr.next;
}
// Else break if a consonant
// node is found
else {
break;
}
}
// This prev node used to link
// prev consonant to next
// consonant after vowels
var prev = ptr;
// Head points to the first
// consonant of the linked list
head = ptr;
ptr = ptr.next;
// Case 2: If vowels found in
// between of the linked list
while (ptr != null) {
// If current node is vowel
if (isVowel(ptr.data)) {
// Move ptr to the next
// node
ptr = ptr.next;
// Check for vowels
// occurring continuously
while (ptr != null) {
// If ptr is a vowel
// move to next pointer
if (isVowel(ptr.data)) {
ptr = ptr.next;
}
// Else break if
// consonant found
else {
break;
}
}
// Case 3: If we have ending
// vowels then link the prev
// consonant to NULL
if (ptr == null) {
prev.next = null;
break;
}
// Case 2: change the next
// link of prev to current
// consonant pointing to
// ptr
else {
prev.next = ptr;
}
}
// Move prev and ptr to next
// for next iteration
prev = prev.next;
ptr = ptr.next;
}
}
// Driver code
// Initialise the Linked List
head = new Node('a');
head.next = new Node('b');
head.next.next = new Node('c');
head.next.next.next = new Node('e');
head.next.next.next.next = new Node('f');
head.next.next.next.next.next = new Node('g');
head.next.next.next.next.next.next = new Node('i');
head.next.next.next.next.next.next.next = new Node('o');
// Print the given Linked List
document.write("Linked list before :<br/>");
printlist(head);
removeVowels();
// Print the Linked List after
// removing vowels
document.write("Linked list after :<br/>");
printlist(head);
// This code is contributed by Rajput-Ji </script> |
Output:
Linked list before : a -> b -> c -> e -> f -> g -> i -> o Linked list after : b -> c -> f -> g
Time Complexity: O(N) where N is the number of nodes in the linked list.
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