Given a string str, the task is to print longest palindrome word present in the string str.
Examples:
Input : Madam Arora teaches Malayalam
Output: Malayalam
Explanation: The string contains three palindrome words (i.e., Madam, Arora, Malayalam) but the length of Malayalam is greater than the other two.
Input : Welcome to GeeksforGeeks
Output : No Palindrome Word
Explanation:The string does not contain any palindrome word so the output is No Palindrome Word.
Approach:
- longestPalin() function finds the longest palindrome word by extracting every word of the string and passing it to checkPalin() function. An extra space is added in the original string to extract last word.
- checkPalin() function checks if the word is palindrome. It returns true if word is palindrome else returns false. It makes sure that empty strings are not counted as palindrome as the user may enter more than one spaces in between or at the beginning of the string.
/* C++ program to print longest palindrome word in a sentence and its length*/ #include <iostream> #include <algorithm> #include <string> using namespace std;
// Function to check if a // word is palindrome bool checkPalin(string word)
{ int n = word.length();
// making the check case
// case insensitive
// word = word.toLowerCase();
transform(word.begin(), word.end(),
word.begin(), :: tolower );
// loop to check palindrome
for ( int i = 0; i < n; i++, n--)
if (word[i] != word[n - 1])
return false ;
return true ;
} // Function to find longest // palindrome word string longestPalin(string str) { // to check last word for palindrome
str = str + " " ;
// to store each word
string longestword = "" , word = "" ;
int length, length1 = 0;
for ( int i = 0; i < str.length(); i++)
{
char ch = str[i];
// extracting each word
if (ch != ' ' )
word = word + ch;
else {
length = word.length();
if (checkPalin(word) &&
length > length1)
{
length1 = length;
longestword = word;
}
word = "" ;
}
}
return longestword;
} // Driver code int main()
{ string s = "My name is ava and i love"
" Geeksforgeeks" ;
if (longestPalin(s) == "" )
cout<< "No Palindrome" << " Word" ;
else
cout<<longestPalin(s);
return 0;
} // This code is contributed by Manish // Shaw (manishshaw1) |
/*Java program to print longest palindrome word in a sentence and its length*/ public class GFG {
// Function to check if a
// word is palindrome
static boolean checkPalin(String word)
{
int n = word.length();
// making the check case
// case insensitive
word = word.toLowerCase();
// loop to check palindrome
for ( int i = 0 ; i < n; i++, n--)
if (word.charAt(i) !=
word.charAt(n - 1 ))
return false ;
return true ;
}
// Function to find longest
// palindrome word
static String longestPalin(String str)
{
// to check last word for palindrome
str = str + " " ;
// to store each word
String longestword = "" , word = "" ;
int length, length1 = 0 ;
for ( int i = 0 ; i < str.length(); i++)
{
char ch = str.charAt(i);
// extracting each word
if (ch != ' ' )
word = word + ch;
else {
length = word.length();
if (checkPalin(word) &&
length > length1)
{
length1 = length;
longestword = word;
}
word = "" ;
}
}
return longestword;
}
// Driver code
public static void main(String args[])
{
String s = new String( "My name is ava "
+ "and i love Geeksforgeeks" );
if (longestPalin(s) == "" )
System.out.println( "No Palindrome"
+ " Word" );
else
System.out.println(longestPalin(s));
}
} |
# Python 3 program to print longest palindrome # word in a sentence and its length # Function to check if a word is palindrome def checkPalin(word):
n = len (word)
# making the check case
# case insensitive
word = word.lower()
# loop to check palindrome
for i in range ( n):
if (word[i] ! = word[n - 1 ]):
return False
n - = 1
return True
# Function to find longest # palindrome word def longestPalin( str ):
# to check last word for palindrome
str = str + " "
# to store each word
longestword = ""
word = ""
length1 = 0
for i in range ( len ( str )):
ch = str [i]
# extracting each word
if (ch ! = ' ' ):
word = word + ch
else :
length = len (word)
if (checkPalin(word) and
length > length1):
length1 = length
longestword = word
word = ""
return longestword
# Driver code if __name__ = = "__main__" :
s = "My name is ava and i love Geeksforgeeks"
if (longestPalin(s) = = ""):
print ( "No Palindrome Word" )
else :
print (longestPalin(s))
# This code is contributed by ita_c |
<script> /*Javascript program to print longest palindrome word in a sentence and its length*/ // Function to check if a
// word is palindrome
function checkPalin(word)
{
let n = word.length;
// making the check case
// case insensitive
word = word.toLowerCase();
// loop to check palindrome
for (let i = 0; i < n; i++, n--)
if (word[i] !=
word[n-1])
return false ;
return true ;
}
// Function to find longest
// palindrome word
function longestPalin(str)
{
// to check last word for palindrome
str = str + " " ;
// to store each word
let longestword = "" , word = "" ;
let length, length1 = 0;
for (let i = 0; i < str.length; i++)
{
let ch = str[i];
// extracting each word
if (ch != ' ' )
word = word + ch;
else {
length = word.length;
if (checkPalin(word) &&
length > length1)
{
length1 = length;
longestword = word;
}
word = "" ;
}
}
return longestword;
}
// Driver code
let s= "My name is ava "
+ "and i love Geeksforgeeks" ;
if (longestPalin(s) == "" )
document.write( "No Palindrome"
+ " Word" );
else
document.write(longestPalin(s));
// This code is contributed by rag2127
</script> |
/* C# program to print longest palindrome word in a sentence and its length*/ using System;
class GFG
{ // Function to check if a
// word is palindrome
static bool checkPalin( string word)
{
int n = word.Length;
// making the check case
// case insensitive
word = word.ToLower();
// loop to check palindrome
for ( int i = 0; i < n; i++, n--)
if (word[i] != word[n - 1])
return false ;
return true ;
}
// Function to find longest
// palindrome word
static string longestPalin( string str)
{
// to check last word for palindrome
str = str + " " ;
// to store each word
string longestword = "" , word = "" ;
int length, length1 = 0;
for ( int i = 0; i < str.Length; i++)
{
char ch = str[i];
// extracting each word
if (ch != ' ' )
word = word + ch;
else {
length = word.Length;
if (checkPalin(word) &&
length > length1)
{
length1 = length;
longestword = word;
}
word = "" ;
}
}
return longestword;
}
// Driver code
public static void Main()
{
string s = "My name is ava and i"
+ " love Geeksforgeeks" ;
if (longestPalin(s) == "" )
Console.Write( "No Palindrome Word" );
else
Console.Write(longestPalin(s));
}
} // This code is contributed by Manish // Shaw (manishshaw1) |
ava
Time complexity : O(n^2)
Space complexity : O(n)
Method #2:Using sorted() method in Python:
- The idea is to split the words of the string into a list .
- Traverse the list and append all palindromic words to new list
- Sort the newlist in increasing order of length of words using the sorted() method.
- Finally, print the last string present in the list.
Below is the implementation of the above approach.:
// C++ program for the above approach #include <iostream> #include <vector> #include <algorithm> using namespace std;
bool isPalindrome(string s) {
return s == string(s.rbegin(), s.rend());
} void largestPalin(vector<string> s) {
// Taking new list
vector<string> newlist;
// Traverse the list
for (string word : s) {
if (isPalindrome(word)) {
newlist.push_back(word);
}
}
// Using sorted() method
sort(newlist.begin(), newlist.end(), [](string a, string b) { return a.size() < b.size(); });
// Print last word
cout << newlist.back() << endl;
} // Driver Code int main() {
// Given string
string str = "My name is ava and i love Geeksforgeeks" ;
vector<string> words;
string word;
for ( char c : str) {
if (c == ' ' ) {
words.push_back(word);
word.clear();
} else {
word += c;
}
}
if (!word.empty()) {
words.push_back(word);
}
largestPalin(words);
return 0;
} // This code is contributed by Prajwal Kandekar |
import java.util.ArrayList;
import java.util.Collections;
public class Main {
// Function to check if a string is a palindrome
public static boolean isPalindrome(String s)
{
return s.equals(
new StringBuilder(s).reverse().toString());
}
// Function to find the largest palindrome in a list of
// words
public static void largestPalin(ArrayList<String> s)
{
// Create a new list to store all the palindromes
// found
ArrayList<String> newlist = new ArrayList<>();
// Iterate over each word in the input list
for (String word : s) {
// Check if the current word is a palindrome
if (isPalindrome(word)) {
// If it is, add it to the new list
newlist.add(word);
}
}
// Sort the new list in ascending order of length
Collections.sort(newlist,
(a, b) -> a.length() - b.length());
// Print the largest palindrome (last element in the
// sorted list)
System.out.println(newlist.get(newlist.size() - 1 ));
}
public static void main(String[] args)
{
// Input string to be processed
String str
= "My name is ava and i love Geeksforgeeks" ;
// Create a list to store all the words in the input
// string
ArrayList<String> words = new ArrayList<>();
// Create a string builder to build each word from
// the input string
StringBuilder word = new StringBuilder();
// Iterate over each character in the input string
for ( char c : str.toCharArray()) {
// If the current character is a space, the
// current word is complete
if (c == ' ' ) {
// Add the current word to the list of words
words.add(word.toString());
// Reset the string builder to build the
// next word
word.setLength( 0 );
}
else {
// Otherwise, append the current character
// to the current word
word.append(c);
}
}
// If there is a word left in the string builder,
// add it to the list of words
if (word.length() > 0 ) {
words.add(word.toString());
}
// Find the largest palindrome in the list of words
largestPalin(words);
}
} |
# Python3 program for the above approach def ispalindrome(string):
if (string = = string[:: - 1 ]):
return True
else :
return False
def largestPalin(s):
# Taking new list
newlist = []
# Traverse the list
for i in s:
if (ispalindrome(i)):
newlist.append(i)
# Using sorted() method
s = sorted (newlist, key = len )
# Print last word
print (s[ len (s) - 1 ])
# Driver Code if __name__ = = "__main__" :
# Given string
s = "My name is ava and i love Geeksforgeeks"
# Convert string to list
l = list (s.split( " " ))
largestPalin(l)
# This code is contributed by vikkycirus |
<script> // JavaScript program for the above approach function ispalindrome(string){
let temp = string
temp = temp.split( '' ).reverse().join( '' )
if (string == temp)
return true
else
return false
} function largestPalin(s){
// Taking new list
let newlist = []
// Traverse the list
for (let i of s){
if (ispalindrome(i))
newlist.push(i)
}
// Using sorted() method
newlist.sort((a,b)=>a.length - b.length)
s = newlist
// Print last word
document.write(s[s.length-1], "</br>" )
} // Driver Code // Given string let s = "My name is ava and i love Geeksforgeeks"
// Convert string to list let l = s.split( " " )
largestPalin(l) // This code is contributed by shinjanpatra </script> |
// C# program for the above approach using System;
using System.Collections.Generic;
using System.Linq;
public class Program {
// Function to check if a string is a palindrome
public static bool IsPalindrome( string s) {
return s.Equals( new string (s.Reverse().ToArray()));
}
// Function to find the largest palindrome in a list of
// words
public static void LargestPalin(List < string > s) {
// Create a new list to store all the palindromes
// found
List < string > newList = new List < string > ();
// Iterate over each word in the input list
foreach ( string word in s) {
// Check if the current word is a palindrome
if (IsPalindrome(word)) {
// If it is, add it to the new list
newList.Add(word);
}
}
// Sort the new list in ascending order of length
newList.Sort((a, b) => a.Length - b.Length);
// Print the largest palindrome (last element in the
// sorted list)
Console.WriteLine(newList[newList.Count - 1]);
}
public static void Main( string [] args) {
// Input string to be processed
string str = "My name is ava and i love Geeksforgeeks" ;
// Create a list to store all the words in the input
// string
List < string > words = new List < string > ();
// Create a string builder to build each word from
// the input string
System.Text.StringBuilder word = new System.Text.StringBuilder();
// Iterate over each character in the input string
foreach ( char c in str) {
// If the current character is a space, the
// current word is complete
if (c == ' ' ) {
// Add the current word to the list of words
words.Add(word.ToString());
// Reset the string builder to build the
// next word
word.Clear();
} else {
// Otherwise, append the current character
// to the current word
word.Append(c);
}
}
// If there is a word left in the string builder,
// add it to the list of words
if (word.Length > 0) {
words.Add(word.ToString());
}
// Find the largest palindrome in the list of words
LargestPalin(words);
}
} // Contributed by adityasharmadev01 |
Output:
ava
Method #3:Using filter() method in Python:
- First, the string is converted into a list of words using the re module.
- Then the filter function is applied to the list of word to, using ispalindrome function to filter out only the palindrome words.
- After max, the function is applied using the len as key to get a word with max length
#include <algorithm> #include <iostream> #include <regex> #include <string> using namespace std;
bool ispalindrome(string word)
{ return word == string(word.rbegin(), word.rend());
} void largestPalin(string s)
{ // Convert string to vector of words
regex pattern(R "(\b\w+\b)" );
vector<string> words(
sregex_token_iterator(s.begin(), s.end(), pattern),
sregex_token_iterator());
// Using remove_if() and erase() functions to remove
// non-palindrome words
words.erase(remove_if(words.begin(), words.end(),
[](string word) {
return !ispalindrome(word);
}),
words.end());
// Using max_element() function to find the word with
// the maximum length
auto it = max_element(
words.begin(), words.end(), [](string a, string b) {
return a.length() < b.length();
});
// Printing the largest palindrome
cout << *it << endl;
} int main()
{ string s = "My name is ava and i love Geeksforgeeks" ;
largestPalin(s);
return 0;
} |
// Java program for the above approach import java.util.ArrayList;
import java.util.List;
public class Main {
public static boolean isPalindrome(String word)
{
return word.equals(
new StringBuilder(word).reverse().toString());
}
public static void largestPalin(String s)
{
// Convert string to list of words
String[] words = s.split( "\\W+" );
List<String> palindromeWords = new ArrayList<>();
// Using filter() function to filter palindrome
// words
for (String word : words) {
if (isPalindrome(word)) {
palindromeWords.add(word);
}
}
// Using max() function to find the word with the
// maximum length
String largestPalindrome
= palindromeWords.stream()
.max((a, b)
-> Integer.compare(a.length(),
b.length()))
.orElse( null );
System.out.println(largestPalindrome);
}
public static void main(String[] args)
{
String s
= "My name is ava and i love Geeksforgeeks" ;
largestPalin(s);
}
} // Contributed by adityasha4x71 |
import re
def ispalindrome(word):
return word = = word[:: - 1 ]
def largestPalin(s):
# Convert string to list of words
words = re.findall(r '\b\w+\b' , s)
# Using filter() function to filter palindrome words
palindrome_words = filter (ispalindrome, words)
# Using max() function to find the word with the maximum length
largest_palindrome = max (palindrome_words, key = len )
print (largest_palindrome)
# Driver Code if __name__ = = "__main__" :
s = "My name is ava and i love Geeksforgeeks"
largestPalin(s)
|
// JavaScript program for above approach function isPalindrome(word) {
return word === word.split( '' ).reverse().join( '' );
} function largestPalin(s) {
// Convert string to array of words
const words = s.match(/\b\w+\b/g);
// Using filter() method to filter palindrome words
const palindromeWords = words.filter(isPalindrome);
// Using reduce() method to find the word with the maximum length
const largestPalindrome = palindromeWords.reduce((a, b) => a.length >= b.length ? a : b, "" );
console.log(largestPalindrome);
} // Driver Code const s = "My name is ava and i love Geeksforgeeks" ;
largestPalin(s); // Contributed by adityasha4x71 |
using System;
using System.Linq;
class Program {
static bool IsPalindrome( string word)
{
return word.SequenceEqual(word.Reverse());
}
static string LargestPalin( string s)
{
// Convert string to array of words
var words = s.Split(
new char [] { ' ' },
StringSplitOptions.RemoveEmptyEntries);
// Using LINQ to filter palindrome words
var palindromeWords = words.Where(IsPalindrome);
// Using LINQ to find the word with the maximum
// length
var largestPalindrome
= palindromeWords
.OrderByDescending(word = > word.Length)
.FirstOrDefault();
return largestPalindrome;
}
static void Main( string [] args)
{
string s
= "My name is ava and i love Geeksforgeeks" ;
string largestPalindrome = LargestPalin(s);
Console.WriteLine(largestPalindrome);
}
} |
ava
Time complexity:O(n)
Auxiliary Space:O(n)