Find a string such that every character is lexicographically greater than its immediate next character

Last Updated : 06 Dec, 2018

Given an integer N, the task is to find a string(considering only lowercase characters) of length (N+1) such that the character at any position should be lexicographically greater than its immediate next character.
Examples:

Input: 2
Output: cba
c is greater than b and
b is greater than a

Input: 5
Output: fedcba

Approach:

Declare a string with all the alphabets in reverse order.
Take modulus of the given number with 26. So, if the value is less than 26, run a loop from 26 – (Modulus Value + 1) to 25 and go to that index of the string and print that index.
Divide the modulus value with 26 if value comes greater than 0 then run the loop to 0 to 25 and print every element of the string by given the calculated value.

Below is the implementation of above approach:

C++

// C++ program to print a string in reverse 
// alphabetical order upto given number 
#include <bits/stdc++.h> 
using namespace std; 
  
// Function that prints the required string 
string printString(int n, string str) 
{ 
    string str2 = ""; 
  
    // Find modulus with 26 
    int extraChar = n % 26; 
  
    // Print extra characters required 
    if (extraChar >= 1) { 
        for (int i = 26 - (extraChar + 1); i <= 25; i++) 
            str2 += str[i]; 
    } 
    int countOfStr = n / 26; 
  
    // Print the given reverse string countOfStr times 
    for (int i = 1; i <= countOfStr; i++) { 
        for (int j = 0; j < 26; j++) 
            str2 += str[j]; 
    } 
    return str2; 
} 
  
// Driver Code 
int main() 
{ 
    int n = 30; 
  
    // Initialize a string in reverse order 
    string str = "zyxwvutsrqponmlkjihgfedcba"; 
  
    cout << printString(n, str); 
  
    return 0; 
} 

Java

// Java program to print a String in reverse  
// alphabetical order upto given number  
  
class GFG { 
  
// Function that prints the required String  
    static String printString(int n, String str) { 
        String str2 = ""; 
  
        // Find modulus with 26  
        int extraChar = n % 26; 
  
        // Print extra characters required  
        if (extraChar >= 1) { 
            for (int i = 26 - (extraChar + 1); i <= 25; i++) { 
                str2 += str.charAt(i); 
            } 
        } 
        int countOfStr = n / 26; 
  
        // Print the given reverse String countOfStr times  
        for (int i = 1; i <= countOfStr; i++) { 
            for (int j = 0; j < 26; j++) { 
                str2 += str.charAt(j); 
            } 
        } 
        return str2; 
    } 
  
// Driver Code  
    public static void main(String[] args) { 
        int n = 30; 
  
        // Initialize a String in reverse order  
        String str = "zyxwvutsrqponmlkjihgfedcba"; 
        System.out.println(printString(n, str)); 
    } 
} 
  
// This code is contributed by Rajput-JI  

Python 3

# Python 3 program to print a  
# string in reverse alphabetical  
# order upto given number 
  
# Function that prints the 
# required string 
def printString(n, str): 
  
    str2 = "" 
  
    # Find modulus with 26 
    extraChar = n % 26
  
    # Print extra characters required 
    if (extraChar >= 1) : 
        for i in range( 26 - (extraChar + 1), 26): 
            str2 += str[i] 
  
    countOfStr = n // 26
  
    # Print the given reverse  
    # string countOfStr times 
    for i in range(1, countOfStr + 1) : 
        for j in range(26): 
            str2 += str[j] 
    return str2 
  
# Driver Code 
if __name__ == "__main__": 
    n = 30
  
    # Initialize a string in  
    # reverse order 
    str = "zyxwvutsrqponmlkjihgfedcba"
  
    print(printString(n, str)) 
  
# This code is contributed  
# by ChitraNayal 

C#

// C# program to print a String in reverse  
// alphabetical order upto given number  
using System; 
public class GFG {  
  
// Function that prints the required String  
    static String printString(int n, String str) { 
        String str2 = ""; 
  
        // Find modulus with 26  
        int extraChar = n % 26; 
  
        // Print extra characters required  
        if (extraChar >= 1) { 
            for (int i = 26 - (extraChar + 1); i <= 25; i++) { 
                str2 += str[i]; 
            } 
        } 
        int countOfStr = n / 26; 
  
        // Print the given reverse String countOfStr times  
        for (int i = 1; i <= countOfStr; i++) { 
            for (int j = 0; j < 26; j++) { 
                str2 += str[j]; 
            } 
        } 
        return str2; 
    } 
  
// Driver Code  
    public static void Main() { 
        int n = 30; 
  
        // Initialize a String in reverse order  
        String str = "zyxwvutsrqponmlkjihgfedcba"; 
        Console.Write(printString(n, str)); 
    } 
} 
  
// This code is contributed by Rajput-JI  

Output:

edcbazyxwvutsrqponmlkjihgfedcba

This article is contributed by Sahil Rajput. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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