Print all words occurring in a sentence exactly K times

Given a string S consisting of lowercase alphabets and an integer K, the task is to print all the words that occur K times in the string S.

Examples:

Input: S = “banana is in yellow and sun flower is also in yellow”, K = 2
Output: “is” “yellow” “in”
Explanation: The words “is”, “yellow” and “in” occurs in the string twice. 

Input: S = “geeks for geeks”, K = 2
Output: “geeks”

Approach: Follow the steps below to solve the problem:

• Initialize a list l to store the words present in the string.
• Split the words and store it in the list.
• Traverse the list and for each word:
  • If the frequency of the word is found to be K:
    • Print that word.
    • Remove current occurrence of that word from the list.

Below is the implementation of the above approach:

C++

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

// Function to print all the words
// occurring k times in a string
void kFreqWords(string S, int K)
{

  // Stores the words
  string temp = "";
  vector<string> l;
  for (auto x: S)
  {
    if(x == ' ')
    {
      l.push_back(temp);
      temp = "";
    }
    else
      temp += x;
  }

  // Traverse the list
  for (auto x: l)
  {

    // Check for count
    if (count(l.begin(), l.end(), x) == K)
    {

      // Print the word
      cout << x << endl;

      // Remove from list
      remove(l.begin(),l.end(), x);
    }
  }
}

// Driver Code
int main()
{

  // Given string
  string S = "banana is in yellow and sun flower is also in yellow ";

  // Given value of K
  int K = 2;

  // Function call to find
  // all words occurring K times
  kFreqWords(S, K);

}

// This code is contributed by SURENDRA_GANGWAR.

Java

// JAVA program for the above approach
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

class GFG {

  // Function to print all the words
  // occurring k times in a String
  static void kFreqWords(String S, int K) {

    // Stores the words
    String temp = "";
    Queue<String> l = new ConcurrentLinkedQueue<String>();
    for (char x : S.toCharArray()) {
      if (x == ' ') {
        l.add(temp);
        temp = "";
      } else
        temp += x;
    }

    // Traverse the list
    for (String x : l) {

      // Check for count
      if (count(l, x) == K) {

        // Print the word
        System.out.print(x + "\n");

        // Remove from list
        l.remove((Object)x);
      }
    }
  }

  // Driver Code
  private static int count(Queue<String> l, String x) {
    int count = 0;
    for (String s : l) {
      if (s.equals(x))
        count++;
    }
    return count;
  }

  public static void main(String[] args) {

    // Given String
    String S = "banana is in yellow and sun flower is also in yellow ";

    // Given value of K
    int K = 2;

    // Function call to find
    // all words occurring K times
    kFreqWords(S, K);

  }
}

// This code is contributed by shikhasingrajput

Python3

# Python3 program for the above approach

# Function to print all the words
# occurring k times in a string


def kFreqWords(S, K):

    # Stores the words
    l = list(S.split(" "))

    # Traverse the list
    for i in l:

        # Check for count
        if l.count(i) == K:

            # Print the word
            print(i)

            # Remove from list
            l.remove(i)


# Driver Code
if __name__ == "__main__":

    # Given string
    S = "banana is in yellow and sun flower is also in yellow"

    # Given value of K
    K = 2

    # Function call to find
    # all words occurring K times
    kFreqWords(S, K)

C#

// C# program for the above approach
using System;
using System.Collections.Generic;

using System.Collections.Concurrent;
public class GFG {

  // Function to print all the words
  // occurring k times in a String
  static void kFreqWords(String S, int K) {

    // Stores the words
    String temp = "";
    List<String> l = new List<String>();
    foreach (char x in S.ToCharArray()) {
      if (x == ' ') {
        l.Add(temp);
        temp = "";
      } else
        temp += x;
    }

    // Traverse the list
    foreach (String x in new List<String>(l)) {

      // Check for count
      if (count(l, x) == K) {

        // Print the word
        Console.Write(x + "\n");

        // Remove from list
        l.Remove(x);
      }
    }
  }

  // Driver Code
  private static int count(List<String> l, String x) {
    int count = 0;
    foreach (String s in l) {
      if (s.Equals(x))
        count++;
    }
    return count;
  }

  public static void Main(String[] args) {

    // Given String
    String S = "banana is in yellow and sun flower is also in yellow ";

    // Given value of K
    int K = 2;

    // Function call to find
    // all words occurring K times
    kFreqWords(S, K);

  }
}



// This code contributed by shikhasingrajput

Javascript

// Function to print all the words
// occurring k times in a string
function kFreqWords(S, K) {
    // Stores the words
    let l = S.split(" ");

    // Traverse the list
    for (let i = 0; i < l.length; i++) {
        // Check for count
        if (l.filter(word => word === l[i]).length === K) {
            // Print the word
            console.log(l[i]);

            // Remove from list
            l = l.filter(word => word !== l[i]);
        }
    }
}

// Driver Code
(function() {
    // Given string
    let S = "banana is in yellow and sun flower is also in yellow";

    // Given value of K
    let K = 2;

    // Function call to find
    // all words occurring K times
    kFreqWords(S, K);
})();

Output

is
yellow
in

Time Complexity: O(N²)
Auxiliary Space: O(N) because using auxiliary space for list to store frequency of word

Method #2: Using built in python functions:

• As all the words in a sentence are separated by spaces.
• We have to split the sentence by spaces using split().
• We split all the words by spaces and store them in a list.
• Use Counter function to count frequency of words
• Traverse the frequency dictionary and print the word having frequency k

Below is the implementation of above approach:

Python3

# Python program for the above approach
from collections import Counter

# Python program to print words
# which occurs k times
def printWords(sentence, k):

    # splitting the string
    lis = list(sentence.split(" "))

    # Calculating frequency of every word
    frequency = Counter(lis)

    # Traversing the frequency
    for i in frequency:

        # checking if frequency is k

        if(frequency[i] == k):

            # print the word
            print(i, end=" ")


# Driver code
# Given string
sentence = "sky is blue and my favourite color is blue"

# Given value of K
K = 2

printWords(sentence, K)
# this code is contributed by vikkycirus

Javascript

<script>
// JavaScript program for the above approach

/*
Function to print words
which occur k times
*/
function printWords(sentence, k)
{

    // splitting the string
    let lis = sentence.split(" ");

    // Calculating frequency of each word
    frequency = {};
    for(const word of lis)
    {

        // if word exists, increase the value by 1, otherwise mark it as 1
        frequency[word] = frequency[word] ? frequency[word] + 1 : 1;
    }

    // Iterating through frequency
    for(const key of Object.keys(frequency)){

        // if frequency is k
        if(frequency[key] == k){

            // print the word
            document.write(key + " ");
        }
    }
}

// Driver code
// Given string
let sentence = "sky is blue and my favourite color is blue"

// Given value of K
let K = 2
printWords(sentence, K)

// This code is contributed by mostaptname
</script>

Output:

is blue 

Time Complexity: O(N)

Space Complexity: O(N)