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Count occurrences of strings formed using words in another string

  • Last Updated : 24 Jan, 2022

Given a string A and a vector of strings B, the task is to count the number of strings in vector B that only contains the words from A.

Examples:

Input: A=”blue green red yellow”
B[]={“blue red”, “green pink”, “yellow green”}
Output: 2

Input: A=”apple banana pear”
B[]={“apple”, “banana apple”, “pear banana”}
Output: 3

Approach: Follow the below steps to solve this problem:

  1. Extract all the words of string A and store them in a set, say st.
  2. Now traverse on each string in vector B, and get all the words in that string.
  3. Now check that if all words are present in st, then increment ans by 1.
  4. Return ans as the solution to the problem.

Below is the implementation of the above approach:

C++




// C++ code for the above approach
 
#include <bits/stdc++.h>
using namespace std;
 
// Function to extract all words from a string
vector<string> getWords(string A)
{
    vector<string> words;
    string t;
    for (int i = 0; i < A.size(); i++) {
 
        // If the character is a space
        if (A[i] == ' ') {
            if (t.size() > 0) {
                words.push_back(t);
            }
            t = "";
        }
 
        // Else
        else {
            t += A[i];
        }
    }
 
    // Last word
    if (t.size() > 0) {
        words.push_back(t);
    }
 
    return words;
}
 
// Function to count the number of strings in B
// that only contains the words from A
int countStrings(string A, vector<string>& B)
{
 
    unordered_set<string> st;
 
    vector<string> words;
    words = getWords(A);
 
    for (auto x : words) {
        st.insert(x);
    }
 
    // Variable to store the final answer
    int ans = 0;
    for (auto x : B) {
        words = getWords(x);
        bool flag = 0;
        for (auto y : words) {
            if (st.find(y) == st.end()) {
                flag = 1;
                break;
            }
        }
 
        // If all the words are in set st
        if (!flag) {
            ans++;
        }
    }
 
    return ans;
}
 
// Driver Code
int main()
{
    string A = "blue green red yellow";
    vector<string> B = { "blue red", "green pink", "yellow green" };
 
    cout << countStrings(A, B);
}

Java




// Java code for the above approach
import java.util.*;
 
class GFG
{
 
  // Function to extract all words from a String
  static Vector<String> getWords(String A)
  {
    Vector<String> words = new Vector<String>();
    String t="";
    for (int i = 0; i < A.length(); i++) {
 
      // If the character is a space
      if (A.charAt(i) == ' ') {
        if (t.length() > 0) {
          words.add(t);
        }
        t = "";
      }
 
      // Else
      else {
        t += A.charAt(i);
      }
    }
 
    // Last word
    if (t.length() > 0) {
      words.add(t);
    }
 
    return words;
  }
 
  // Function to count the number of Strings in B
  // that only contains the words from A
  static int countStrings(String A, String[] B)
  {
 
    HashSet<String> st = new HashSet<>();
 
    Vector<String> words = new Vector<String>();
    words = getWords(A);
 
    for (String x : words) {
      st.add(x);
    }
 
    // Variable to store the final answer
    int ans = 0;
    for (String x : B) {
      words = getWords(x);
      boolean flag = false;
      for (String y : words) {
        if (!st.contains(y)) {
          flag = true;
          break;
        }
      }
 
      // If all the words are in set st
      if (!flag) {
        ans++;
      }
    }
 
    return ans;
  }
 
  // Driver Code
  public static void main(String[] args)
  {
    String A = "blue green red yellow";
    String []B = { "blue red", "green pink", "yellow green" };
 
    System.out.print(countStrings(A, B));
  }
}
 
// This code is contributed by 29AjayKumar

Python3




# Python 3  code for the above approach
 
# Function to extract all words from a string
def getWords(A):
    words = []
    t = ""
    for i in range(len(A)):
 
        # If the character is a space
        if (A[i] == ' '):
            if (len(t) > 0):
                words.append(t)
 
            t = ""
 
        # Else
        else:
            t += A[i]
 
    # Last word
    if (len(t) > 0):
        words.append(t)
 
    return words
 
# Function to count the number of strings in B
# that only contains the words from A
def countStrings(A, B):
    st = set([])
 
    words = []
    words = getWords(A)
 
    for x in words:
        st.add(x)
 
    # Variable to store the final answer
    ans = 0
    for x in B:
        words = getWords(x)
        flag = 0
        for y in words:
            if (y not in st):
                flag = 1
                break
 
        # If all the words are in set st
        if (not flag):
            ans += 1
 
    return ans
 
# Driver Code
if __name__ == "__main__":
 
    A = "blue green red yellow"
    B = ["blue red", "green pink", "yellow green"]
 
    print(countStrings(A, B))
 
    # This code is contributed by ukasp.

C#




// C# code for the above approach
using System;
using System.Collections.Generic;
 
public class GFG
{
 
  // Function to extract all words from a String
  static List<String> getWords(String A)
  {
    List<String> words = new List<String>();
    String t="";
    for (int i = 0; i < A.Length; i++) {
 
      // If the character is a space
      if (A[i] == ' ') {
        if (t.Length > 0) {
          words.Add(t);
        }
        t = "";
      }
 
      // Else
      else {
        t += A[i];
      }
    }
 
    // Last word
    if (t.Length > 0) {
      words.Add(t);
    }
 
    return words;
  }
 
  // Function to count the number of Strings in B
  // that only contains the words from A
  static int countStrings(String A, String[] B)
  {
 
    HashSet<String> st = new HashSet<String>();
 
    List<String> words = new List<String>();
    words = getWords(A);
 
    foreach (String x in words) {
      st.Add(x);
    }
 
    // Variable to store the readonly answer
    int ans = 0;
    foreach (String x in B) {
      words = getWords(x);
      bool flag = false;
      foreach (String y in words) {
        if (!st.Contains(y)) {
          flag = true;
          break;
        }
      }
 
      // If all the words are in set st
      if (!flag) {
        ans++;
      }
    }
 
    return ans;
  }
 
  // Driver Code
  public static void Main(String[] args)
  {
    String A = "blue green red yellow";
    String []B = { "blue red", "green pink", "yellow green" };
 
    Console.Write(countStrings(A, B));
  }
}
 
// This code is contributed by 29AjayKumar

Javascript




  <script>
      // JavaScript code for the above approach
 
      // Function to extract all words from a string
      function getWords(A) {
          let words = [];
          let t;
          for (let i = 0; i < A.length; i++) {
 
              // If the character is a space
              if (A[i] == ' ') {
                  if (t.length > 0) {
                      words.push(t);
                  }
                  t = "";
              }
 
              // Else
              else {
                  t += A[i];
              }
          }
 
          // Last word
          if (t.length > 0) {
              words.push(t);
          }
 
          return words;
      }
 
      // Function to count the number of strings in B
      // that only contains the words from A
      function countStrings(A, B) {
 
          let st = new Set();
 
          let words;
          words = getWords(A);
 
          for (let x of words) {
              st.add(x);
          }
 
          // Variable to store the final answer
          let ans = 0;
          for (let x of B) {
              words = getWords(x);
              let flag = 0;
              for (let y = 0; y < words.length; y++) {
                  if (st.has(words[y])) {
                      flag = 1;
                      break;
                  }
              }
 
              // If all the words are in set st
              if (flag == 0) {
                  ans++;
              }
          }
 
          return ans + 1;
      }
 
      // Driver Code
      let A = "blue green red yellow";
      let B = ["blue red", "green pink", "yellow green"];
 
      document.write(countStrings(A, B));
 
 
// This code is contributed by Potta Lokesh
  </script>

 
 

Output
2

 

Time Complexity: O(N*M), where N is the size of vector B and M is the maximum length of in B.
Auxiliary Space: O(N)

 


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