Generate a string with maximum possible alphabets with odd frequencies

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Given an integer N, the task is to generate a string str which contains maximum possible lowercase alphabets with each of them appearing an odd number of times.
Examples:

Input: N = 17
Output: bcdefghijklmnopqr
Explanation: In order to maximize the number of characters, any 17 characters can be selected and made to appear once. Thus, abcdefghijklmnopq, bcdefghijklmnopqx, etc can be also be valid outputs.
Input: N = 35
Output: bcdefghijklmnopqrstuvwxyaaaaaaaaaaa
Explanation: In order to maximize the number of characters, add any 24 different characters once, and fill the remaining length by any other character.

Approach:

If N is less than equal to 26, we fill the string by N different characters each appearing once.
Otherwise:
- If N is odd, we add all 24 characters from ‘b’-‘y’ once and fill the remaining odd length by ‘a’.
- If N is even, we add all 25 characters from ‘b’-‘z’ once and fill the remaining odd length by ‘a’.

Below is the implementation of the above approach:

C++

// C++ program to generate a string 
// of length n with maximum possible 
// alphabets with each of them 
// occurring odd number of times. 
 
#include <bits/stdc++.h> 
using namespace std; 
 
// Function to generate a string 
// of length n with maximum possible 
// alphabets each occurring odd 
// number of times. 
string generateTheString(int n) 
{ 
    string ans=""; 
    // If n is odd 
    if(n%2) 
    { 
        // Add all characters from 
        // b-y 
        for(int i=0;i<min(n,24);i++) 
        { 
            ans+=(char)('b' + i); 
        } 
        // Append a to fill the 
        // remaining length 
        if(n>24) 
        { 
            for(int i=0;i<(n-24);i++) 
                ans+='a'; 
        } 
    } 
    // If n is even 
    else
    { 
        // Add all characters from 
        // b-z 
        for(int i=0;i<min(n,25);i++) 
        { 
            ans+=(char)('b' + i); 
        } 
        // Append a to fill the 
        // remaining length 
        if(n>25) 
        { 
            for(int i=0;i<(n-25);i++) 
                ans+='a'; 
        } 
    } 
     
    return ans; 
} 
 
// Driven code 
int main() 
{ 
    int n = 34; 
    cout << generateTheString(n); 
    return 0; 
} 

Java

// Java program to generate a string
// of length n with maximum possible
// alphabets with each of them
// occurring odd number of times.
import java.util.*;
 
class GFG{
     
// Function to generate a string
// of length n with maximum possible
// alphabets each occurring odd
// number of times.
static String generateTheString(int n)
{
    String ans = "";
     
    // If n is odd
    if (n % 2 != 0)
    {
 
        // Add all characters from
        // b-y
        for(int i = 0; 
                i < Math.min(n, 24); i++)
        {
            ans += (char)('b' + i);
        }
         
        // Append a to fill the
        // remaining length
        if (n > 24) 
        {
            for(int i = 0; 
                    i < (n - 24); i++)
                ans += 'a';
        }
    }
     
    // If n is even
    else
    {
         
        // Add all characters from
        // b-z
        for(int i = 0; 
                i < Math.min(n, 25); i++)
        {
            ans += (char)('b' + i);
        }
 
        // Append a to fill the
        // remaining length
        if (n > 25) 
        {
            for(int i = 0; 
                    i < (n - 25); i++)
                ans += 'a';
        }
    }
    return ans;
}
 
// Driver code
public static void main(String[] args)
{
    int n = 34;
     
    System.out.println(generateTheString(n));
}
}
 
// This code is contributed by offbeat

Python3

# Python3 program to generate a string 
# of length n with maximum possible
# alphabets with each of them
# occurring odd number of times.
 
# Function to generate a string
# of length n with maximum possible 
# alphabets each occurring odd 
# number of times.
def generateTheString( n):
 
    ans = ""
     
    # If n is odd
    if(n % 2):
         
        # Add all characters from
        # b-y
        for i in range(min(n, 24)):
            ans += chr(ord('b') + i)
         
        # Append a to fill the 
        # remaining length
        if(n > 24):
            for i in range((n - 24)):
                ans += 'a'
         
    # If n is even
    else:
         
        # Add all characters from
        # b-z
        for i in range(min(n, 25)):
            ans += chr(ord('b') + i)
         
        # Append a to fill the 
        # remaining length
        if(n > 25):
            for i in range((n - 25)):
                ans += 'a'
    return ans
 
# Driver code
if __name__ == "__main__":
     
    n = 34
    print(generateTheString(n))
 
# This code is contributed by chitranayal

C#

// C# program to generate a string 
// of length n with maximum possible 
// alphabets with each of them 
// occurring odd number of times. 
using System; 
class GFG{ 
 
// Function to generate a string 
// of length n with maximum possible 
// alphabets each occurring odd 
// number of times. 
static string generateTheString(int n) 
{ 
    string ans = ""; 
     
    // If n is odd 
    if(n % 2 == 0) 
    { 
        // Add all characters from 
        // b-y 
        for(int i = 0; i < Math.Min(n, 24); i++) 
        { 
            ans += (char)('b' + i); 
        } 
         
        // Append a to fill the 
        // remaining length 
        if(n > 24) 
        { 
            for(int i = 0; i < (n - 24); i++) 
                ans += 'a'; 
        } 
    } 
     
    // If n is even 
    else
    { 
        // Add all characters from 
        // b-z 
        for(int i = 0; i < Math.Min(n, 25); i++) 
        { 
            ans += (char)('b' + i); 
        } 
         
        // Append a to fill the 
        // remaining length 
        if(n > 25) 
        { 
            for(int i = 0; i < (n - 25); i++) 
                ans += 'a'; 
        } 
    } 
    return ans; 
} 
 
// Driven code 
public static void Main() 
{ 
    int n = 34; 
    Console.Write(generateTheString(n)); 
} 
} 
 
// This code is contributed by Nidhi_Biet 

Javascript

<script>
 
// Javascript program to generate a string 
// of length n with maximum possible 
// alphabets with each of them 
// occurring odd number of times. 
 
// Function to generate a string 
// of length n with maximum possible 
// alphabets each occurring odd 
// number of times. 
function generateTheString(n) 
{ 
    var ans=""; 
    // If n is odd 
    if(n%2) 
    { 
        // Add all characters from 
        // b-y 
        for(var i=0;i<min(n,24);i++) 
        { 
            ans+=(char)('b' + i); 
        } 
        // Append a to fill the 
        // remaining length 
        if(n>24) 
        { 
            for(var i=0;i<(n-24);i++) 
                ans+='a'; 
        } 
    } 
    // If n is even 
    else
    { 
        // Add all characters from 
        // b-z 
        for(var i=0;i<Math.min(n,25);i++) 
        { 
            ans+= String.fromCharCode('b'.charCodeAt(0) + i); 
        } 
        // Append a to fill the 
        // remaining length 
        if(n>25) 
        { 
            for(var i=0;i<(n-25);i++) 
                ans+='a'; 
        } 
    } 
     
    return ans; 
} 
 
// Driven code 
var n = 34; 
document.write( generateTheString(n)); 
 
</script>

Output:

bcdefghijklmnopqrstuvwxyzaaaaaaaaa

Time Complexity: O(n)
Auxiliary Space: O(n), where n is a given integer.

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