Check if all given strings are isograms or not

Check if a string is Isogram or not

Last Updated : 19 Sep, 2022

Try it on GfG Practice

Given a word or phrase, check if it is an isogram or not. An Isogram is a word in which no letter occurs more than once

Examples:

Input: Machine
Output: True
Explanation: “Machine” does not have any character repeating, it is an Isogram

Input : Geek
Output : False
Explanation: “Geek” has ‘e’ as repeating character, it is not an Isogram

Check if a string is Isogram or not using sorting:

To solve the problem follow the below idea:

Sort the string and for every character check, if the current character is equal to the previous character or not. If it is equal then the string is not an isogram

Follow the given steps to solve the problem:

Convert the string into lowercase English letters
Sort the string
Traverse the string and check for every character
- If the current character is equal to the character on the previous index then return false
Return true

Below is the implementation of the above approach:

C++

// C++ program to check
// If a given string is isogram or not
#include <bits/stdc++.h>
using namespace std;
 
// Function to check
// If a given string is isogram or not
string is_isogram(string str)
{
    int len = str.length();
 
    // Convert the string in lower case letters
    for (int i = 0; i < len; i++)
        str[i] = tolower(str[i]);
 
    sort(str.begin(), str.end());
 
    for (int i = 0; i < len; i++) {
        if (str[i] == str[i + 1])
            return "False";
    }
    return "True";
}
 
// Driver code
int main()
{
    string str1 = "Machine";
   
      // Function call
    cout << is_isogram(str1) << endl;
 
    string str2 = "isogram";
   
      // Function call
    cout << is_isogram(str2) << endl;
 
    string str3 = "GeeksforGeeks";
   
      // Function call
    cout << is_isogram(str3) << endl;
 
    string str4 = "Alphabet";
   
      // Function call
    cout << is_isogram(str4) << endl;
 
    return 0;
}
 
// Contributed by nuclode

Java

// Java program to check
// if a given string is isogram or not
import java.io.*;
import java.util.*;
 
class GFG {
    // Function to check
    // if a given string is isogram or not
    static boolean is_isogram(String str)
    {
        // Convert the string in lower case letters
        str = str.toLowerCase();
        int len = str.length();
 
        char arr[] = str.toCharArray();
 
        Arrays.sort(arr);
        for (int i = 0; i < len - 1; i++) {
            if (arr[i] == arr[i + 1])
                return false;
        }
        return true;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        String str1 = "Machine";
       
          // Function call
        System.out.println(is_isogram(str1));
 
        String str2 = "isogram";
       
          // Function call
        System.out.println(is_isogram(str2));
 
        String str3 = "GeeksforGeeks";
       
          // Function call
        System.out.println(is_isogram(str3));
 
        String str4 = "Alphabet";
       
          // Function call
        System.out.println(is_isogram(str4));
    }
}
 
// Contributed by Pramod Kumar

Python3

# Python program to check
# if a word is isogram or not
 
 
def is_isogram(word):
 
    # Convert the word or sentence in lower case letters.
    clean_word = word.lower()
 
    # Make an empty list to append unique letters
    letter_list = []
 
    for letter in clean_word:
 
        # If letter is an alphabet then only check
        if letter.isalpha():
            if letter in letter_list:
                return False
            letter_list.append(letter)
 
    return True
 
# Driver code
if __name__ == '__main__':
   
      # Function call
    print(is_isogram("Machine"))
    print(is_isogram("isogram"))
    print(is_isogram("GeeksforGeeks"))
    print(is_isogram("Alphabet "))

C#

// C# program to check if a given
// string is isogram or not
using System;
 
public class GFG {
     
    // Function to check if a given
    // string is isogram or not
    static bool is_isogram(string str)
    {
        // Convert the string in lower case letters
        str = str.ToLower();
        int len = str.Length;
 
        char[] arr = str.ToCharArray();
 
        Array.Sort(arr);
        for (int i = 0; i < len - 1; i++) {
            if (arr[i] == arr[i + 1])
                return false;
        }
        return true;
    }
 
    // Driver code
    public static void Main()
    {
        string str1 = "Machine";
       
          // Function call
        Console.WriteLine(is_isogram(str1));
 
        string str2 = "isogram";
       
          // Function call
        Console.WriteLine(is_isogram(str2));
 
        string str3 = "GeeksforGeeks";
       
          // Function call
        Console.WriteLine(is_isogram(str3));
 
        string str4 = "Alphabet";
       
          // Function call
        Console.WriteLine(is_isogram(str4));
    }
}
 
// This code is contributed by Sam007

Javascript

<script>
    // Javascript program to check if a given
    // string is isogram or not
     
    // Function to check if a given
    // string is isogram or not
    function is_isogram(str)
    {
        // Convert the string in lower case letters
        str = str.toLowerCase();
        let len = str.length;
  
        let arr = str.split('');
  
        arr.sort();
        for (let i = 0; i < len - 1; i++) {
            if (arr[i] == arr[i + 1])
                return false;
        }
        return true;
    }
     
    let str1 = "Machine";
    if(is_isogram(str1))
    {
        document.write("True" + "</br>");
    }
    else{
        document.write("False" + "</br>");
    }
 
    let str2 = "isogram";
    if(is_isogram(str2))
    {
        document.write("True" + "</br>");
    }
    else{
        document.write("False" + "</br>");
    }
 
    let str3 = "GeeksforGeeks";
    if(is_isogram(str3))
    {
        document.write("True" + "</br>");
    }
    else{
        document.write("False" + "</br>");
    }
 
    let str4 = "Alphabet";
    if(is_isogram(str4))
    {
        document.write("True" + "</br>");
    }
    else{
        document.write("False" + "</br>");
    }
     
    // This code is contributed by suresh07.
</script>

Output

True
True
False
False

Time Complexity: O(N log N)
Auxiliary Space: O(1)

Check if a string is Isogram or not using Hash-Map:

To solve the problem follow the below idea:

In this, the count of characters of the string is stored in the hashmap, and wherever it is found to be greater than 1 for any char, return false else return true at the end

Follow the given steps to solve the problem:

Declare a hashmap to store the count of the characters of the string
Traverse the string
- Increase the count of the current character in the hashmap
- If the count of the current character is greater than one then return false
Return true

Below is the implementation of the above approach:

C++

// CPP code to check string is isogram or not
#include <bits/stdc++.h>
 
using namespace std;
 
// function to check isogram
bool check_isogram(string str)
{
 
    int length = str.length();
    int mapHash[26] = { 0 };
 
    // loop to store count of chars and check if it is
    // greater than 1
    for (int i = 0; i < length; i++) {
        mapHash[str[i] - 'a']++;
 
        // if count > 1, return false
        if (mapHash[str[i] - 'a'] > 1) {
            return false;
        }
    }
 
    return true;
}
 
// Driver code
int main()
{
    string str = "geeks";
    string str2 = "computer";
 
    // checking str as isogram
    if (check_isogram(str)) {
        cout << "True" << endl;
    }
    else {
        cout << "False" << endl;
    }
 
    // checking str2 as isogram
    if (check_isogram(str2)) {
        cout << "True" << endl;
    }
    else {
        cout << "False" << endl;
    }
 
    return 0;
}

Java

// Java code to check string is isogram or not
import java.io.*;
 
class GFG {
 
    // function to check isogram
    static boolean check_isogram(String str)
    {
 
        int length = str.length();
        int mapHash[] = new int[26];
 
        // loop to store count of chars and
        // check if it is greater than 1
        for (int i = 0; i < length; i++) {
            mapHash[str.charAt(i) - 'a']++;
 
            // if count > 1, return false
            if (mapHash[str.charAt(i) - 'a'] > 1) {
                return false;
            }
        }
 
        return true;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        String str = "geeks";
        String str2 = "computer";
 
        // checking str as isogram
        if (check_isogram(str))
            System.out.println("True");
        else
            System.out.println("False");
 
        // checking str2 as isogram
        if (check_isogram(str2))
            System.out.println("True");
        else
            System.out.println("False");
    }
}
 
// This code contributed by Rajput-Ji

Python3

# Python3 code to check string is isogram or not
 
# function to check isogram
 
 
def check_isogram(string):
 
    length = len(string)
    mapHash = [0] * 26
 
    # loop to store count of chars
    # and check if it is greater than 1
    for i in range(length):
 
        mapHash[ord(string[i]) - ord('a')] += 1
 
        # if count > 1, return false
        if (mapHash[ord(string[i]) - ord('a')] > 1):
 
            return False
 
    return True
 
 
# Driver code
if __name__ == "__main__":
 
    string = "geeks"
    string2 = "computer"
 
    # checking str as isogram
    if (check_isogram(string)):
        print("True")
    else:
        print("False")
 
    # checking str2 as isogram
    if (check_isogram(string2)):
        print("True")
 
    else:
        print("False")
 
# This code is contributed by AnkitRai01

C#

// C# code to check string is isogram or not
using System;
public class GFG {
 
    // function to check isogram
    static bool check_isogram(String str)
    {
 
        int length = str.Length;
        int[] mapHash = new int[26];
 
        // loop to store count of chars and
        // check if it is greater than 1
        for (int i = 0; i < length; i++) {
            mapHash[str[i] - 'a']++;
 
            // if count > 1, return false
            if (mapHash[str[i] - 'a'] > 1) {
                return false;
            }
        }
 
        return true;
    }
 
    // Driver code
    public static void Main(String[] args)
    {
        String str = "geeks";
        String str2 = "computer";
 
        // checking str as isogram
        if (check_isogram(str))
            Console.WriteLine("True");
        else
            Console.WriteLine("False");
 
        // checking str2 as isogram
        if (check_isogram(str2))
            Console.WriteLine("True");
        else
            Console.WriteLine("False");
    }
}
 
// This code has been contributed by 29AjayKumar

Javascript

<script>
    // Javascript code to check string is isogram or not 
     
    // function to check isogram 
    function check_isogram(str) 
    { 
 
        let length = str.length; 
        let mapHash = new Array(26);
        mapHash.fill(0);
 
        // loop to store count of chars and 
        // check if it is greater than 1 
        for (let i = 0; i < length; i++) 
        { 
            mapHash[str[i].charCodeAt() - 'a'.charCodeAt()]++; 
 
            // if count > 1, return false 
            if (mapHash[str[i].charCodeAt() - 'a'.charCodeAt()] > 1) 
            { 
                return false; 
            } 
        } 
 
        return true; 
    } 
     
    let str = "geeks"; 
    let str2 = "computer"; 
    
    // checking str as isogram 
    if (check_isogram(str)) 
        document.write("True" + "</br>");
    else
        document.write("False" + "</br>");
    
    // checking str2 as isogram 
    if (check_isogram(str2)) 
          document.write("True" + "</br>");
    else
        document.write("False" + "</br>");
     
    // This code is contributed by divyeshrabadiya07.
</script>

Output

False
True

Time Complexity: O(N)
Auxiliary Space: O(1), as an array of fixed size 26 is used.

Thanks Sahil Bansal for suggesting the above method.
If you like GeeksforGeeks (We know you do!) and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org.

Check if all given strings are isograms or not

S

Sakshi Tiwari

News

Improve

Article Tags :

Practice Tags :

Similar Reads

Check if a string is Isogram or not

Given a word or phrase, check if it is an isogram or not. An Isogram is a word in which no letter occurs more than once Examples: Input: MachineOutput: TrueExplanation: "Machine" does not have any character repeating, it is an Isogram Input : GeekOutput : FalseExplanation: "Geek" has 'e' as repeatin

Check if all given strings are isograms or not

Given an array arr containing N strings, the task is to check if all strings are isogram or not. If they are, print Yes, otherwise No. An Isogram is a word in which no letter occurs more than once. Examples: Input: arr[] = {"abcd", "derg", "erty"}Output: Yes Input: arr[] = {"agka", "lkmn"}Output: No

Check if the given string is linear or not

Given string str, the task is to check whether the given string is linear or not. If it is linear then print "Yes" else print "No". Let the string be "abcdefghij". It can be broken as: "a" "bc" "def" "ghij" if the character a, b, c, and are equal then the given string is linear otherwise not. Theref

Check if given String is Pangram or not

Given a string s, the task is to check if it is Pangram or not. A pangram is a sentence containing all letters of the English Alphabet. Examples: Input: s = "The quick brown fox jumps over the lazy dog" Output: trueExplanation: The input string contains all characters from â€˜aâ€™ to â€˜zâ€™. Input: s = "Th

Check whether a given string is Heterogram or not

Given a string S. The task is to check whether a the given string is Heterogram or not. A heterogram is a word, phrase, or sentence in which no letter of the alphabet occurs more than once. Examples: Input : S = "the big dwarf only jumps" Output : Yes Each alphabet in the string S is occurred only o

Python set to check if string is pangram

Given a string, check if the given string is a pangram or not. Examples: Input : The quick brown fox jumps over the lazy dog Output : The string is a pangram Input : geeks for geeks Output : The string is not pangram A normal way would have been to use frequency table and check if all elements were

Check if two strings are same or not

Given two strings, the task is to check if these two strings are identical(same) or not. Consider case sensitivity. Examples: Input: s1 = "abc", s2 = "abc" Output: Yes Input: s1 = "", s2 = "" Output: Yes Input: s1 = "GeeksforGeeks", s2 = "Geeks" Output: No Approach - By Using (==) in C++/Python/C#,

Check if a String is Interleaving of Other Two

Given strings s1, s2, and s3, find whether s3 is formed by an interleaving of s1 and s2.Interleaving of two strings s1 and s2 is a way to mix their characters to form a new string s3, while maintaining the relative order of characters from s1 and s2. Conditions for interleaving: Characters from s1 m

Check if two strings are k-anagrams or not

Given two strings of lowercase alphabets and a value k, the task is to find if two strings are K-anagrams of each other or not. Note: Two strings are called k-anagrams if the following two conditions are true. Both have same number of characters.Two strings can become anagram by changing at most k c

Count of Isogram strings in given Array of Strings

Given an array arr[] containing N strings, the task is to find the count of strings which are isograms. A string is an isogram if no letter in that string appears more than once. Examples: Input: arr[] = {"abcd", "derg", "erty"}Output: 3Explanation: All given strings are isograms. In all the strings