Print longest palindrome word in a sentence
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++
/* 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
/*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)); } } |
Python3
# 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 |
C#
/* 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) |
Javascript
<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> |
Output:
ava
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.:
Python3
# 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 |
Javascript
<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> |
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
Python3
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) |
Output
ava
Time complexity:O(n)
Auxiliary Space:O(n)
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