Print Words with Prime length from a Sentence

Given a string S, the task is to print all words with prime length in the given string.

Examples:

Input: S = “This is a python programming language”
Output: is
programming
Explanation: Length of is is 2 and length of programming is 11 both are primes

Input: S = “You are using geeksforgeeks”
Output: You
are
using
geeksforgeeks

Approach 1: 

To solve the problem follow the below steps:

• First split the given string to get an array of space-separated strings.
• Start traversing the words from left to right.
  • Calculate the length of each word.
  • If the length is prime, then print the word.

Below is the implementation of the above approach:

C++

#include <bits/stdc++.h>
using namespace std;

bool isPrime(int x)
{
    // This flag maintains status whether the
    // x is prime or not
    int prime = 0;
    if (x == 2)
        return 1;
    if (x > 1) {
        for (int i = 2; i < sqrt(x) + 1; i++) {
            if (x % i == 0) {
                prime = 1;
                break;
            }
        }
        if (prime == 0)
            return true;
        else
            return false;
    }
    else
        return false;
}

void printPrimeLenWords(string& s)
{
    s += ' ';
    string temp;
    for (int i = 0; i < s.length(); i++) {
        if (s[i] == ' ') {
            // Checking if length of the word
            // is prime
            if (isPrime(temp.size())) {
                cout << temp << "\n";
            }
            temp = "";
        }
        else
            temp += s[i];
    }
}

// Driver Code
int main()
{
    string s = "This is a python programming language";
    printPrimeLenWords(s);
    return 0;
}

// This code is contributed by Rohit Pradhan

Java

/*package whatever //do not write package name here */
import java.io.*;

class GFG {

  public static boolean isPrime(int x)
  {

    // This flag maintains status whether the
    // x is prime or not
    int prime = 0;
    if (x == 2)
      return true;
    if (x > 1) {
      for (int i = 2; i < Math.sqrt(x) + 1; i++) {
        if (x % i == 0) {
          prime = 1;
          break;
        }
      }
      if (prime == 0)
        return true;
      else
        return false;
    }
    else
      return false;
  }

  public static void printPrimeLenWords(String s)
  {
    s += " ";
    String temp = "";
    for (int i = 0; i < s.length(); i++) {
      if (s.charAt(i) == ' ') {
        // Checking if length of the word
        // is prime
        if (isPrime(temp.length())) {
          System.out.println(temp);
        }
        temp = "";
      }
      else
        temp += s.charAt(i);
    }
  }

  public static void main(String[] args)
  {
    String s = "This is a python programming language";
    printPrimeLenWords(s);
  }
}

// This code is contributed by aadityaburujwale.

Python3

# Python program to print all words with
# prime length in the given string.

# Function to check element is prime
from math import sqrt

def isPrime(x):
# This flag maintains status whether the
# x is prime or not
    prime = 0
    if(x > 1):
        for i in range(2, int(sqrt(x)) + 1):
            if (x % i == 0):
                prime = 1
                break
        if (prime == 0):
            return True
        else:
            return False
    else:
        return False

def printPrimeLenWords(s):

    # Splitting the sentence at spaces
    s = s.split()
    for i in s:

        # Checking if length of the word
        # is prime
        if isPrime(len(i)):
            print(i)

# Driver code
if __name__ == '__main__':
    st = "This is a python programming language"

    # Function call
    printPrimeLenWords(st)

C#

using System;
public class GFG {

  public static bool isPrime(int x)
  {

    // This flag maintains status whether the
    // x is prime or not
    int prime = 0;
    if (x == 2)
      return true;
    if (x > 1) {
      for (int i = 2; i < Math.Sqrt(x) + 1; i++) {
        if (x % i == 0) {
          prime = 1;
          break;
        }
      }
      if (prime == 0)
        return true;
      else
        return false;
    }
    else
      return false;
  }

  public static void printPrimeLenWords(string s)
  {
    s += ' ';
    string temp = "";
    for (int i = 0; i < s.Length; i++) {
      if (s[i] == ' ') {
        // Checking if length of the word
        // is prime
        if (isPrime(temp.Length)) {
          Console.WriteLine(temp);
        }
        temp = "";
      }
      else
        temp += s[i];
    }
  }

  // Driver Code
  static public void Main()
  {
    string s = "This is a python programming language";
    printPrimeLenWords(s);
  }
}

// This code is contributed by akashish__

Javascript

       // JavaScript code for the above approach

       // Function to check element is prime
       function isPrime(x)
       {

           // This flag maintains status whether the
           // x is prime or not
           prime = 0
           if (x == 2) return 1
           if (x > 1) {
               for (let i = 2; i < Math.sqrt(x) + 1; i++) {
                   if (x % i == 0) {
                       prime = 1
                       break
                   }
               }
               if (prime == 0)
                   return true
               else
                   return false
           }
           else
               return false
       }
       function printPrimeLenWords(s) {

           // Splitting the sentence at spaces
           s = s.split(' ')

           for (let i = 0; i < s.length; i++)

               // Checking if length of the word
               // is prime
               if (isPrime(s[i].length))
                   console.log(s[i])
       }

       // Driver code
       st = "This is a python programming language"

       // Function call
       printPrimeLenWords(st)

// This code is contributed by Potta Lokesh

Output

is
programming

Time complexity: O(n * sqrt(x)), where n is the number of words in the given sentence and x be the length of the largest string.
Auxiliary Space: O(1)

Approach 2:

Step 1: Initially store all the prime number uptill the pow(10, 5) using the Sieve of Eratosthenes into a set data structure.
Step 2: Run the for loop for  every word and search the length of that word into the set.
Step 3: If word length is present then print else continue.

Implementation for the above approach : –

C++

// C++ Implementation for the above approach
#include<bits/stdc++.h>
using namespace std;

void SieveOfEratosthenes(int n, set<int> &store)
{
    bool prime[n+1];
    memset(prime, true, sizeof(prime));

    for (int p=2; p*p<=n; p++)
    {
        // If prime[p] is not changed, then it is a prime
        if (prime[p] == true)
        {
            // Update all multiples of p
            for (int i=p*2; i<=n; i += p)
                prime[i] = false;
        }
    }

    // Print all prime numbers
    for (int p=2; p<=n; p++)
       if (prime[p])
          store.insert(p);
}

int main(){
    set<int> store;
    string s = "This is a python programming language";
    SieveOfEratosthenes(s.size(), store);
      // for getting the every word from the sentence
    istringstream iss(s);
    string word;
      // looping for extracting the every word length
    while(iss >> word){
        if(store.find(word.size()) != store.end()){
            cout << word << endl;
        }
    }
    return 0;
}

Java

// Java Implementation for the above approach
import java.io.*;
import java.util.*;

class GFG {

  static Set<Integer> store = new HashSet<>();

  static void SieveOfEratosthenes(int n)
  {
    boolean[] prime = new boolean[n + 1];
    Arrays.fill(prime, true);
    for (int p = 2; p * p <= n; p++) {

      // If prime[p] is not changed, then it is a
      // prime
      if (prime[p] == true) {
        for (int i = p * 2; i <= n; i += p) {
          prime[i] = false;
        }
      }
    }

    // Print all prime numbers
    for (int p = 2; p <= n; p++) {
      if (prime[p]) {
        store.add(p);
      }
    }
  }

  public static void main(String[] args)
  {
    String s = "This is a python programming language";
    SieveOfEratosthenes(s.length());

    // for getting the every word from the sentence
    String[] words = s.split(" ");

    // looping for extracting the every word length
    for (String word : words) {
      if (store.contains(word.length())) {
        System.out.println(word);
      }
    }
  }
}

// This code is contributed by karthik.

Python3

# Python Implementation for the above approach

def SieveOfEratosthenes( n, store):
    prime=[1]*(n+1);

    p=2;
    while(p*p<=n):
        # If prime[p] is not changed, then it is a prime
        if (prime[p] == True):
            # Update all multiples of p
            for i in range(2*p, n+1, p):
                prime[i] = False;
        p+=1;
    # Print all prime numbers
    for p in range(2,n+1,1):
       if (prime[p]):
          store.add(p);

store=set();
s = "This is a python programming language";
SieveOfEratosthenes(len(s), store);
  # for getting the every word from the sentence
words=s.split();
  # looping for extracting the every word length
for i in range (0,len(words)):
    #if(store.find(word.size()) != store.end()){
    word=words[i];
    if(len(word) in store):
        print(word);

C#

// C# Implementation for the above approach

using System;
using System.Collections.Generic;

public class GFG {

    static HashSet<int> store = new HashSet<int>();

    static void SieveOfEratosthenes(int n)
    {
        bool[] prime = new bool[n + 1];
        for (int i = 0; i <= n; i++) {
            prime[i] = true;
        }

        for (int p = 2; p * p <= n; p++) {
            if (prime[p] == true) {
                for (int i = p * 2; i <= n; i += p) {
                    prime[i] = false;
                }
            }
        }

        for (int p = 2; p <= n; p++) {
            if (prime[p]) {
                store.Add(p);
            }
        }
    }

    static public void Main()
    {

        // Code
        string s = "This is a python programming language";
        SieveOfEratosthenes(s.Length);

        string[] words = s.Split(" ");
        foreach(string word in words)
        {
            if (store.Contains(word.Length)) {
                Console.WriteLine(word);
            }
        }
    }
}

// This code is contributed by lokesh.

Javascript

// JavaScript Implementation for the above approach

function SieveOfEratosthenes(n, store) {
      let prime = Array(n + 1).fill(true);

      for (let p = 2; p * p <= n; p++) {
        // If prime[p] is not changed, then it is a prime
        if (prime[p] === true) {
          // Update all multiples of p
          for (let i = p * 2; i <= n; i += p) {
            prime[i] = false;
          }
        }
      }

      // Print all prime numbers
      for (let p = 2; p <= n; p++) {
        if (prime[p]) {
          store.add(p);
        }
      }
    }


    let store = new Set();
    let s = 'This is a python programming language';
    SieveOfEratosthenes(s.length, store);

    // for getting the every word from the sentence
    let words = s.split(' ');

    // looping for extracting the every word length
    for (let word of words) {
      if (store.has(word.length)) {
        document.write(word);
        document.write("<br>");
      }
    }

Output

is
programming

Time complexity: O(n*log(logn)), where n = size of string
Auxiliary Space: O(n)

Approach 3:

Step 1: Iterate over the characters of the string one by one.
Step 2: Whenever we encounter a space character, we check if the length of the word is prime or not. 
Step 3: If it is, we print the word. We also check same for the last word which is not followed by a space character.

Below is the implementation of the above approach.

C++

// C++ Implementation for the above approach

#include <bits/stdc++.h>
using namespace std;

bool isPrime(int p)
{
    if (p <= 1)
        return false;
    else if (p == 2 || p == 3)
        return true;
    else if (p % 2 == 0 || p % 3 == 0)
        return false;
    else {
        for (int i = 5; i * i <= p; i += 6) {
            if (p % i == 0 || p % (i + 2) == 0)
                return false;
        }
    }
    return true;
}

int main()
{
    string s = "This is a python programming language";
    string word;

    for (int i = 0; i < s.length(); i++) {
        if (s[i] != ' ') {
            word += s[i];
        }
        else {
            if (isPrime(word.length())) {
                cout << word << endl;
            }
            word.clear();
        }
    }
    if (isPrime(word.length())) {
        cout << word << endl;
    }

    return 0;
}

// This code is contributed by Susobhan Akhuli

Java

// Java Implementation for the above approach

import java.util.*;

public class Main {
    // Function to check whether a number is prime or not
    static boolean isPrime(int p)
    {
        if (p <= 1)
            return false;
        else if (p == 2 || p == 3)
            return true;
        else if (p % 2 == 0 || p % 3 == 0)
            return false;
        else {
            for (int i = 5; i * i <= p; i += 6) {
                if (p % i == 0 || p % (i + 2) == 0)
                    return false;
            }
        }
        return true;
    }

    public static void main(String[] args)
    {
        String s = "This is a python programming language";
        String word = "";

        // Loop through each character of the input string
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) != ' ') {
                word += s.charAt(i);
            }
            else {
                if (isPrime(word.length())) {
                    System.out.println(word);
                }
                word = "";
            }
        }

        // Check the last word separately since it won't
        // have a space after it
        if (isPrime(word.length())) {
            System.out.println(word);
        }
    }
}

// This code is contributed by rishabmalhdijo

Python3

import math

# Function to check if a number is prime or not
def isPrime(p):
    if p <= 1:
        return False
    elif p == 2 or p == 3:
        return True
    elif p % 2 == 0 or p % 3 == 0:
        return False
    else:
        for i in range(5, int(math.sqrt(p)) + 1, 6):
            if p % i == 0 or p % (i + 2) == 0:
                return False
    return True

s = "This is a python programming language"
word = ""

# Loop through each character in the string
for i in range(len(s)):
    if s[i] != " ":
        word += s[i]
    else:
        if isPrime(len(word)):
            print(word)
        word = ""

# Check if the last word is prime
if isPrime(len(word)):
    print(word)

C#

// C# Implementation for the above approach
using System;

class Gfg{

    static bool isPrime(int p)
    {
        if (p <= 1)
            return false;
        else if (p == 2 || p == 3)
            return true;
        else if (p % 2 == 0 || p % 3 == 0)
            return false;
        else {
            for (int i = 5; i * i <= p; i += 6) {
                if (p % i == 0 || p % (i + 2) == 0)
                    return false;
            }
        }
        return true;
    }

    public static void Main()
    {
        string s = "This is a python programming language";
        string word="";

        for (int i = 0; i < s.Length; i++) {
            if (s[i] != ' ') {
                word += s[i];
            }
            else {
                if (isPrime(word.Length)) {
                    Console.WriteLine(word);
                }
                word="";
            }
        }
        if (isPrime(word.Length)) {
            Console.WriteLine(word);
        }

    }
}

Javascript

function isPrime(p) {
    if (p <= 1)
        return false;
    else if (p == 2 || p == 3)
        return true;
    else if (p % 2 == 0 || p % 3 == 0)
        return false;
    else {
        for (let i = 5; i * i <= p; i += 6) {
            if (p % i == 0 || p % (i + 2) == 0)
                return false;
        }
    }
    return true;
}

let s = "This is a python programming language";
let word = "";

for (let i = 0; i < s.length; i++) {
    if (s[i] != " ") {
        word += s[i];
    } else {
        if (isPrime(word.length)) {
            console.log(word);
        }
        word = "";
    }
}

if (isPrime(word.length)) {
    console.log(word);
}

Output

is
programming

Time complexity: O(N*sqrt(N)), where N is the length of the string.
Auxiliary Space: O(K),  where K is the length of the biggest word in the string.

Approach 4:

Step 1: First split the sentence into words using repeted iteration of getline() function.
Step 2: In each iteartion, we check if the length of the word is prime or not using Wilson Primality Test.
Step 3: If it is prime, then we print the word.

C++

// C++ Implementation for the above approach
#include <bits/stdc++.h>
using namespace std;

// Function to calculate the factorial
long long fact(const int& p)
{
    if (p <= 1)
        return 1;
    return p * fact(p - 1);
}

// Function to check if the
// number is prime or not
// using Wilson Primality Test
bool isPrime(const long long& p)
{
    if (p == 4 || p <= 1)
        return false;

    //  (p - 1) ! ≡  (p-1) mod p
    long long a = fact(p - 1) % p;
    if (a == p - 1)
        return true;
    return false;
}

int main()
{
    string s = "This is a python programming language";
    string word;

      istringstream iss(s);
    while (getline(iss, word, ' ')) {
          if (isPrime(word.length()))
            cout << word << endl;
    }
    return 0;
}

// This code is contributed by Susobhan Akhuli

Java

// Java Implementation for the above approach
import java.io.*;
import java.util.*;

public class GFG {
    // Function to calculate the factorial
    public static long fact(final int p) {
        if (p <= 1) {
            return 1;
        }
        return p * fact(p - 1);
    }

    // Function to check if the
    // number is prime or not
    // using Wilson Primality Test
    public static boolean isPrime(final long p) {
        if (p == 4 || p <= 1) {
            return false;
        }
        // (p - 1) ! ≡ (p-1) mod p
        final long a = fact((int) (p - 1)) % p;
        if (a == p - 1) {
            return true;
        }
        return false;
    }

    public static void main(final String[] args) {
        final String s = "This is a python programming language";
        String word;

        final Scanner iss = new Scanner(s);
        iss.useDelimiter(" ");
        while (iss.hasNext()) {
            word = iss.next();
            if (isPrime(word.length())) {
                System.out.println(word);
            }
        }
        iss.close();
    }
}

// This code is contributed by Susobhan Akhuli

Python3

# Python Implementation for the above approach

# Function to calculate the factorial
def fact(p):
    if p <= 1:
        return 1
    return p * fact(p - 1)

# Function to check if the
# number is prime or not
# using Wilson Primality Test
def isPrime(p):
    if p == 4 or p <= 1:
        return False

    #  (p - 1) ! ≡  (p-1) mod p
    a = fact(p - 1) % p
    if a == p - 1:
        return True
    return False

s = "This is a python programming language"
words = s.split(' ')

for word in words:
    if isPrime(len(word)):
        print(word)

# This code is contributed by Susobhan Akhuli

Output

is
programming

Time complexity: O(N*K), where N is the length of the sentence and K is the length of the biggest word in the string.
Auxiliary Space: O(K)