Missing characters to make a string Pangram

Last Updated : 19 Oct, 2023

Pangram is a sentence containing every letter in the English alphabet. Given a string, find all characters that are missing from the string, i.e., the characters that can make the string a Pangram. We need to print output in alphabetic order.

Examples:

Input : welcome to geeksforgeeks
Output : abdhijnpquvxyz
Input : The quick brown fox jumps
Output : adglvyz

Approach 1: Using a set to keep track of present characters

Initialize an empty set to keep track of the present characters.
Iterate through each character in the input string.
If the character is a lowercase letter, add it to the set.
If the character is an uppercase letter, convert it to lowercase and add it to the set.
Initialize an empty string to store the missing characters.
Iterate through each lowercase letter from ‘a’ to ‘z’.
If the letter is not in the set, append it to the missing characters string.
If the missing characters string is empty, the input string is a pangram.
Otherwise, the missing characters string contains the characters that need to be added to the input string to make it a pangram. Print this string as the output.

C++

   #include <iostream>
#include <string>
#include <algorithm>
#include <set>
using namespace std;
 
int main() {
    string str = "The quick brown fox jumps over the dog";
    set<char> present_chars;
 
    // add each character to the set
    for(int i=0; i<str.length(); i++){
        if (str[i] >= 'a' && str[i] <= 'z'){
            present_chars.insert(str[i]);
        }
        else if (str[i] >= 'A' && str[i] <= 'Z'){
            present_chars.insert(tolower(str[i]));
        }
    }
 
    // check which characters are missing
    string missing_chars = "";
    for(char c='a'; c<='z'; c++){
        if(present_chars.find(c) == present_chars.end()){
            missing_chars += c;
        }
    }
 
    // print the missing characters
    if(missing_chars.length() == 0){
        cout << "The string is a pangram." << endl;
    }
    else{
        cout <<  missing_chars << endl;
    }
 
    return 0;
}
 
  

Java

   import java.util.HashSet;
 
public class Main {
 
    public static void main(String[] args) {
        String str = "The quick brown fox jumps over the dog";
        HashSet<Character> presentChars = new HashSet<>();
 
        // add each character to the set
        for(int i = 0; i < str.length(); i++){
            char c = str.charAt(i);
            if (c >= 'a' && c <= 'z'){
                presentChars.add(c);
            }
            else if (c >= 'A' && c <= 'Z'){
                presentChars.add(Character.toLowerCase(c));
            }
        }
 
        // check which characters are missing
        StringBuilder missingChars = new StringBuilder();
        for(char c = 'a'; c <= 'z'; c++){
            if(!presentChars.contains(c)){
                missingChars.append(c);
            }
        }
 
        // print the missing characters
        if(missingChars.length() == 0){
            System.out.println("The string is a pangram.");
        }
        else{
            System.out.println(missingChars);
        }
    }
}
 
  

Python

   def main():
    str_ = "The quick brown fox jumps over the dog"
     
    # Use a set to store present characters
    present_chars = set()
 
    # Add each character to the set
    for char in str_:
        if char.isalpha():
            present_chars.add(char.lower())
 
    # Check which characters are missing
    missing_chars = "".join(c for c in "abcdefghijklmnopqrstuvwxyz" if c not in present_chars)
 
    # Print the missing characters
    if not missing_chars:
        print("The string is a pangram.")
    else:
        print(missing_chars)
 
if __name__ == "__main__":
    main()
 
# This Code Is Contributed By Shubham Tiwari
 
  

C#

   using System;
using System.Collections.Generic;
 
public class GFG {
    public static void Main() {
        string str = "The quick brown fox jumps over the dog";
        HashSet<char> presentChars = new HashSet<char>();
 
        // add each character to the set
        foreach (char c in str) {
            if (Char.IsLetter(c)) {
                presentChars.Add(Char.ToLower(c));
            }
        }
 
        // check which characters are missing
        string missingChars = "";
        for (char c='a'; c<='z'; c++) {
            if (!presentChars.Contains(c)) {
                missingChars += c;
            }
        }
 
        // print the missing characters
        if (missingChars.Length == 0) {
            Console.WriteLine("The string is a pangram.");
        }
        else {
            Console.WriteLine(missingChars);
        }
    }
}
// This Code Is Contributed By Shubham Tiwari
 
  

Javascript

   // Function to find missing characters in a string to make it a pangram
function findMissingChars(str) {
    const presentChars = new Set();
 
    // Add each character to the set
    for (let i = 0; i < str.length; i++) {
        const char = str[i].toLowerCase();
        if (char >= 'a' && char <= 'z') {
            presentChars.add(char);
        }
    }
 
    // Check which characters are missing
    let missingChars = '';
    for (let c = 'a'; c <= 'z'; c = String.fromCharCode(c.charCodeAt(0) + 1)) {
        if (!presentChars.has(c)) {
            missingChars += c;
        }
    }
 
    // Print the missing characters or indicate that the string is a pangram
    if (missingChars.length === 0) {
        console.log('The string is a pangram.');
    } else {
        console.log(missingChars);
    }
}
 
// Example usage
const str = "The quick brown fox jumps over the dog";
findMissingChars(str);
 
  

Output

alyz

Time Complexity: O(nlogn)
Auxiliary Space: O(n)

We have discussed Pangram Checking. The idea is similar, we traverse a given string and mark all visited characters. In the end, we print all those characters which are not visited.

Lowercase and Uppercase characters are considered the same.

C++

   // C++ program to find characters that needs
// to be added to make Pangram
#include<bits/stdc++.h>
using namespace std;
const int MAX_CHAR = 26;
 
// Returns characters that needs to be added
// to make str
string missingChars(string str)
{
    // A boolean array to store characters
    // present in string.
    bool present[MAX_CHAR] = {false};
 
    // Traverse string and mark characters
    // present in string.
    for (int i=0; i<str.length(); i++)
    {
        if (str[i] >= 'a' && str[i] <= 'z')
            present[str[i]-'a'] = true;
        else if (str[i] >= 'A' && str[i] <= 'Z')
            present[str[i]-'A'] = true;
    }
 
    // Store missing characters in alphabetic
    // order.
    string res = "";
    for (int i=0; i<MAX_CHAR; i++)
        if (present[i] == false)
            res.push_back((char)(i+'a'));
 
    return res;
}
 
// Driver program
int main()
{
    string str = "The quick brown fox jumps "
                 "over the dog";
    cout << missingChars(str);
    return 0;
}        
 
  

Java

   // Java program to find characters that
// needs to be added to make Pangram 
import java.io.*;
import java.util.ArrayList;
 
class GFG{
     
private static ArrayList<Character>missingChars(
    String str, int strLength)
{
    final int MAX_CHARS = 26;
     
    // A boolean array to store characters 
    // present in string.
    boolean[] present = new boolean[MAX_CHARS];
    ArrayList<Character> charsList = new ArrayList<>();
     
    // Traverse string and mark characters 
    // present in string. 
    for(int i = 0; i < strLength; i++) 
    {
        if ('A' <= str.charAt(i) && 
                   str.charAt(i) <= 'Z')
            present[str.charAt(i) - 'A'] = true;
        else if ('a' <= str.charAt(i) && 
                        str.charAt(i) <= 'z')
            present[str.charAt(i) - 'a'] = true;
    }
     
    // Store missing characters in alphabetic 
    // order. 
    for(int i = 0; i < MAX_CHARS; i++) 
    {
        if (present[i] == false)
            charsList.add((char)(i + 'a'));
    }
    return charsList;
}
 
// Driver Code
public static void main(String[] args)
{
    String str = "The quick brown fox jumps " +
                 "over the dog"; 
                  
    ArrayList<Character> missing = GFG.missingChars(
        str, str.length());
         
    if (missing.size() >= 1)
    {
        for(Character character : missing)
        {
            System.out.print(character);
        }
    }
}
}
 
// This code is contributed by theSardul
 
  

Python3

   # Python3 program to find characters 
# that needs to be added to make Pangram 
MAX_CHAR = 26
 
# Returns characters that needs 
# to be added to make str 
def missingChars(Str):
     
    # A boolean array to store characters 
    # present in string. 
    present = [False for i in range(MAX_CHAR)]
 
    # Traverse string and mark characters 
    # present in string. 
    for i in range(len(Str)):
        if (Str[i] >= 'a' and Str[i] <= 'z'):
            present[ord(Str[i]) - ord('a')] = True
        else if (Str[i] >= 'A' and Str[i] <= 'Z'):
            present[ord(Str[i]) - ord('A')] = True
 
    # Store missing characters in alphabetic 
    # order. 
    res = ""
 
    for i in range(MAX_CHAR):
        if (present[i] == False):
            res += chr(i + ord('a'))
             
    return res
 
# Driver code
Str = "The quick brown fox jumps over the dog"
 
print(missingChars(Str))
 
# This code is contributed by avanitrachhadiya2155
 
  

C#

   // C# program to find characters that
// needs to be added to make Pangram 
using System.Collections.Generic; 
using System; 
class GFG{
     
static List<char>missingChars (String str, 
                               int strLength)
{
  int MAX_CHARS = 26;
 
  // A boolean array to store 
  // characters present in string.
  bool[] present = new bool[MAX_CHARS];
  List<char>charsList = new List<char>();
 
  // Traverse string and mark 
  // characters present in string. 
  for(int i = 0; i < strLength; i++) 
  {
    if ('A' <= str[i] && 
        str[i] <= 'Z')
      present[str[i] - 'A'] = true;
    else if ('a' <= str[i] && 
             str[i] <= 'z')
      present[str[i] - 'a'] = true;
  }
 
  // Store missing characters 
  // in alphabetic order. 
  for(int i = 0; i < 26; i++) 
  {
    if (present[i] == false)
    {
      charsList.Add((char)(i + 'a'));
    }
  }
  return charsList;
}
 
// Driver Code
public static void Main()
{
  String str = "The quick brown fox jumps over the dog"; 
  List<char> missing = missingChars(str, 
                                    str.Length);
  if (missing.Count >= 1)
  {
    foreach (var i in missing)
    {
      Console.Write(i);
    }
  }
}
}
 
// This code is contributed by Stream_Cipher
 
  

Javascript

   <script>
    // Javascript program to find characters that
    // needs to be added to make Pangram
     
    function missingChars (str, strLength)
    {
      let MAX_CHARS = 26;
 
      // A boolean array to store
      // characters present in string.
      let present = new Array(MAX_CHARS);
      present.fill(false);
      let charsList = [];
 
      // Traverse string and mark
      // characters present in string.
      for(let i = 0; i < strLength; i++)
      {
        if ('A'.charCodeAt() <= str[i].charCodeAt() && str[i].charCodeAt() <= 'Z'.charCodeAt())
          present[str[i].charCodeAt() - 'A'.charCodeAt()] = true;
        else if ('a'.charCodeAt() <= str[i].charCodeAt() && str[i].charCodeAt() <= 'z'.charCodeAt())
          present[str[i].charCodeAt() - 'a'.charCodeAt()] = true;
      }
 
      // Store missing characters
      // in alphabetic order.
      for(let i = 0; i < 26; i++)
      {
        if (present[i] == false)
        {
          charsList.push(String.fromCharCode(i + 'a'.charCodeAt()));
        }
      }
      return charsList;
    }
     
    let str = "The quick brown fox jumps over the dog";
    let missing = missingChars(str, str.length);
    if (missing.length >= 1)
    {
      for(let i = 0; i < missing.length; i++)
      {
        document.write(missing[i]);
      }
    }
 
// This code is contributed by mukesh07.
</script>
 
  

Output

alyz

Time Complexity: O(n)
Auxiliary Space: O(1)

Check if a string is Pangrammatic Lipogram

kartik

Improve

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Missing characters to make a string Pangram

C++

Java

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C#

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Java

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C#

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