Count of strings that does not contain any character of a given string

Given an array arr containing N strings and a string str, the task is to find the number of strings that do not contain any character of string str.

Examples:

Input: arr[] = {“abcd”, “hijk”, “xyz”, “ayt”}, str=”apple”
Output: 2
Explanation: “hijk” and “xyz” are the strings that do not contain any character of str

Input: arr[] = {“apple”, “banana”, “pear”}, str=”nil”
Output: 1

Approach: Follow the below steps to solve this problem:

1. Create a set st and store each character of string str in this set.
2. Create a variable ans to store the number of all the required strings.
3. Now, start traversing on the array and for each string, check if any of its character is present in the set st or not. If it is, then this is not a required string.
4. If it doesn’t contain any character from the set, increase answer by 1.
5. Return ans after the loop ends, as the answer to this 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 count the number of strings
// that does not contain any character of string str
int allowedStrings(vector<string>& arr, string str)
{
    int ans = 0;
    unordered_set<char> st;
    for (auto x : str) {
        st.insert(x);
    }

    for (auto x : arr) {
        bool allowed = 1;
        for (auto y : x) {

            // If the character is present in st
            if (st.find(y) != st.end()) {
                allowed = 0;
                break;
            }
        }

        // If the string doesn't
        // have any character of st
        if (allowed) {
            ans += 1;
        }
    }

    return ans;
}

// Driver Code
int main()
{
    vector<string> arr
        = { "abcd", "hijk", "xyz", "ayt" };
    string str = "apple";
    cout << allowedStrings(arr, str);
}

Java

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

class GFG {

  // Function to count the number of strings
  // that does not contain any character of string str
  public static int allowedStrings(List<String> arr,
                                   String str)
  {
    int ans = 0;
    Set<Character> st = new HashSet<Character>();

    char[] chararray = str.toCharArray();
    for (Character x : chararray) {
      st.add(x);
    }

    for (int i = 0; i < arr.size(); i++) {
      String x = arr.get(i);
      boolean allowed = true;
      char[] chararray2 = x.toCharArray();
      for (Character y : chararray2) {

        // If the character is present in st
        if (st.contains(y)) {
          allowed = false;
          break;
        }
      }

      // If the string doesn't
      // have any character of st
      if (allowed) {
        ans += 1;
      }
    }

    return ans;
  }

  public static void main(String[] args)
  {
    List<String> arr = new ArrayList<String>();
    arr.add("abcd");
    arr.add("hijk");
    arr.add("xyz");
    arr.add("ayt");
    String str = "apple";
    System.out.println(allowedStrings(arr, str));
  }
}

// This code is contributed by akashish__

Python3

# Python 3 code for the above approach

# Function to count the number of strings
# that does not contain any character of string str
def allowedStrings(arr, st):
    ans = 0
    st1 = set([])
    for x in st:
        st1.add(x)

    for x in arr:
        allowed = 1
        for y in x:

            # If the character is present in st1
            if (y in st1):
                allowed = 0
                break

        # If the string doesn't
        # have any character of st
        if (allowed):
            ans += 1

    return ans

# Driver Code
if __name__ == "__main__":

    arr = ["abcd", "hijk", "xyz", "ayt"]
    st = "apple"
    print(allowedStrings(arr, st))

    # This code is contributed by ukasp.

C#

using System;
using System.Collections.Generic;

public class GFG{

  // Function to count the number of strings
  // that does not contain any character of string str
  public static int allowedStrings(List<String> arr,
                                   String str)
  {
    int ans = 0;
    HashSet<char> st = new HashSet<char>();

    for(int i=0;i<str.Length;i++)
    {
      st.Add(str[i]);
    }

    for (int i = 0; i < arr.Count; i++) {
      String x = arr[i];
      bool allowed = true;
      for (int j=0;j<x.Length;j++) {

        // If the character is present in st
        if (st.Contains(x[j])) {
          allowed = false;
          break;
        }
      }

      // If the string doesn't
      // have any character of st
      if (allowed==true) {
        ans += 1;
      }
    }

    return ans;
  }

  static public void Main (){

    List<String> arr = new List<String>();
    arr.Add("abcd");
    arr.Add("hijk");
    arr.Add("xyz");
    arr.Add("ayt");
    String str = "apple";
    Console.WriteLine(allowedStrings(arr, str));

  }
}
// This code is contributed by akashish__

Javascript

<script>
// Javascript code for the above approach

// Function to count the number of strings
// that does not contain any character of string str
function allowedStrings(arr, str)
{
    let ans = 0;
    let st = new Set();
    for (x of str) {
        st.add(x);
    }

    for (x of arr) {
        let allowed = 1;
        for (y of x) {

            // If the character is present in st
            if (st.has(y)) {
                allowed = 0;
                break;
            }
        }

        // If the string doesn't
        // have any character of st
        if (allowed) {
            ans += 1;
        }
    }

    return ans;
}

// Driver Code

let arr = ["abcd", "hijk", "xyz", "ayt"];
let str = "apple";
document.write(allowedStrings(arr, str));

// This code is contributed by gfgking.
</script>

Output

2

Time Complexity: O(N*M), where N is the size of the array and M is the size of the longest string.
Auxiliary Space: O(N)

Approach:

To solve this problem is to iterate through each string in the given array and for each string, iterate through each character in the given string str. If a character in str is found in the current string, then we break the loop and move to the next string in the array. If none of the characters in str are found in the current string, then we increment a counter variable that keeps track of the number of strings that do not contain any character of str.

Implementation of the above approach:

C++

// C++ code for the above approach

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

// Function to count the number of strings
// that does not contain any character of string str
int allowedStrings(vector<string>& arr, string str)
{
    int count = 0;
    for (string s : arr) {
        bool flag = true;
        for (char c : str) {
            if (s.find(c) != string::npos) {
                flag = false;
                break;
            }
        }
        if (flag) {
            count++;
        }
    }
    return count;
}

// Driver Code
int main()
{
    vector<string> arr
        = { "abcd", "hijk", "xyz", "ayt" };
    string str = "apple";
    cout << allowedStrings(arr, str);
}

Java

import java.util.*;

public class Main {
    // Function to count the number of strings
    // that does not contain any character of string str
    public static int allowedStrings(List<String> arr, String str) {
        int count = 0;
        for (String s : arr) {
            boolean flag = true;
            for (char c : str.toCharArray()) {
                if (s.indexOf(c) != -1) {
                    flag = false;
                    break;
                }
            }
            if (flag) {
                count++;
            }
        }
        return count;
    }

    // Driver Code
    public static void main(String[] args) {
        List<String> arr = Arrays.asList("abcd", "hijk", "xyz", "ayt");
        String str = "apple";
        System.out.println(allowedStrings(arr, str));
    }
}

C#

using System;
using System.Collections.Generic;

public class MainClass
{
    // Function to count the number of strings
    // that does not contain any character of string str
    public static int allowedStrings(List<string> arr, string str)
    {
        int count = 0;
        foreach (string s in arr)
        {
            bool flag = true;
            foreach (char c in str)
            {
                if (s.Contains(c))
                {
                    flag = false;
                    break;
                }
            }
            if (flag)
            {
                count++;
            }
        }
        return count;
    }

    // Driver Code
    public static void Main()
    {
        List<string> arr = new List<string> { "abcd", "hijk", "xyz", "ayt" };
        string str = "apple";
        Console.WriteLine(allowedStrings(arr, str));
    }
}

Output

2

Time Complexity: O(N*M)

Space Complexity: O(1)