Sort an Array alphabetically when each number is converted into words

Last Updated : 12 Jul, 2025

Given an array arr[] containing N non-negative integers, the task is to sort these integers alphabetically when each number is converted into words.

Examples:

Input: arr[] = {12, 10, 102, 31, 15}
Output: 15 102 10 31 12
Explanation:
The above set of numbers are sorted alphabetically. That is:
15 -> Fifteen
102 -> One hundred and two
10 -> Ten
31 -> Thirty-one
12 -> Twelve

Input: arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
Output: 8 5 4 9 1 7 6 10 3 2
Explanation:
The above set of numbers are sorted alphabetically. That is:
8 -> eight
5 -> five
4 -> four
9 -> nine
1 -> one
7 -> seven
6 -> six
10 -> ten
3 -> three
2 -> two

Approach: In order to sort the numbers alphabetically, we first need to convert the number to its word form. Therefore, the idea is to store each element along with its word form in a vector pair and then sort all the elements of the vector according to the corresponding words of the number. Therefore:

Precompute and store the word forms of all the units digits in an array.
Precompute and store the word forms of all the tens digits in another array.
For all the remaining numbers greater than 2 digits, the number is divided and the word form is added.
Iterate through every digit of the number in the array arr[] and store the corresponding word form of the numbers in a vector as a pair.
Iterate through the vector and sort the vector according to the words.
Finally, print the sorted order.

Below is the implementation of the above approach:

C++

// C++ program to sort an array of
// integers alphabetically

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

// Variable to store the word form of
// units digit and up to twenty
string one[]
    = { "", "one ", "two ", "three ",
        "four ", "five ", "six ",
        "seven ", "eight ", "nine ", "ten ",
        "eleven ", "twelve ", "thirteen ",
        "fourteen ", "fifteen ", "sixteen ",
        "seventeen ", "eighteen ", "nineteen " };

// Variable to store the word form of
// tens digit
string ten[]
    = { "", "", "twenty ",
        "thirty ", "forty ",
        "fifty ", "sixty ",
        "seventy ", "eighty ",
        "ninety " };

// Function to convert a two digit number
// to the word by using the above defined arrays
string numToWords(int n, string s)
{
    string str = "";

    // If n is more than 19, divide it
    if (n > 19)
        str += ten[n / 10] + one[n % 10];
    else
        str += one[n];

    // If n is non-zero
    if (n)
        str += s;

    return str;
}

// Function to print a given number in words
string convertToWords(int n)
{
    // Stores the word representation
    // of the given number n
    string out;

    // Handles digits at ten millions
    // and hundred millions places
    out += numToWords((n / 10000000),
                      "crore ");

    // Handles digits at hundred thousands
    // and one millions places
    out += numToWords(((n / 100000) % 100),
                      "lakh ");

    // Handles digits at thousands and
    // tens thousands places
    out += numToWords(((n / 1000) % 100),
                      "thousand ");

    // Handles digit at hundreds places
    out += numToWords(((n / 100) % 10),
                      "hundred ");

    if (n > 100 && n % 100)
        out += "and ";

    // Call the above function to convert
    // the number into words
    out += numToWords((n % 100), "");

    return out;
}

// Function to sort the array according to
// the albhabetical order
void sortArr(int arr[], int n)
{
    // Vector to store the number in words
    // with respective elements
    vector<pair<string, int> > vp;

    // Inserting number in words
    // with respective elements in vector pair
    for (int i = 0; i < n; i++) {
        vp.push_back(make_pair(
            convertToWords(arr[i]), arr[i]));
    }

    // Sort the vector, this will sort the pair
    // according to the alphabetical order.
    sort(vp.begin(), vp.end());

    // Print the sorted vector content
    for (int i = 0; i < vp.size(); i++)
        cout << vp[i].second << " ";
}

// Driver code
int main()
{
    int arr[] = { 12, 10, 102, 31, 15 };
    int n = sizeof(arr) / sizeof(arr[0]);

    sortArr(arr, n);

    return 0;
}

Java

// Java program to sort an array of
// integers alphabetically
import java.util.*;

class GFG{
    static class pair implements Comparable<pair>
    { 
        String first;
        int second; 
        public pair(String first, int second)  
        { 
            this.first = first; 
            this.second = second; 
        }
        @Override
        public int compareTo(pair o) 
        {
          
            // TODO Auto-generated method stub
            return this.first.compareTo(o.first);
        }    
    } 
  
// Variable to store the word form of
// units digit and up to twenty
static String one[]
    = { "", "one ", "two ", "three ",
        "four ", "five ", "six ",
        "seven ", "eight ", "nine ", "ten ",
        "eleven ", "twelve ", "thirteen ",
        "fourteen ", "fifteen ", "sixteen ",
        "seventeen ", "eighteen ", "nineteen " };

// Variable to store the word form of
// tens digit
static String ten[]
    = { "", "", "twenty ",
        "thirty ", "forty ",
        "fifty ", "sixty ",
        "seventy ", "eighty ",
        "ninety " };

// Function to convert a two digit number
// to the word by using the above defined arrays
static String numToWords(int n, String s)
{
    String str = "";

    // If n is more than 19, divide it
    if (n > 19)
        str += ten[n / 10] + one[n % 10];
    else
        str += one[n];

    // If n is non-zero
    if (n>0)
        str += s;

    return str;
}

// Function to print a given number in words
static String convertToWords(int n)
{
  
    // Stores the word representation
    // of the given number n
    String out = "";

    // Handles digits at ten millions
    // and hundred millions places
    out += numToWords((n / 10000000),
                      "crore ");

    // Handles digits at hundred thousands
    // and one millions places
    out += numToWords(((n / 100000) % 100),
                      "lakh ");

    // Handles digits at thousands and
    // tens thousands places
    out += numToWords(((n / 1000) % 100),
                      "thousand ");

    // Handles digit at hundreds places
    out += numToWords(((n / 100) % 10),
                      "hundred ");

    if (n > 100 && n % 100!=0)
        out += "and ";

    // Call the above function to convert
    // the number into words
    out += numToWords((n % 100), "");

    return out;
}

// Function to sort the array according to
// the albhabetical order
static void sortArr(int arr[], int n)
{
  
    // Vector to store the number in words
    // with respective elements
    Vector<pair> vp = new Vector<pair>();

    // Inserting number in words
    // with respective elements in vector pair
    for (int i = 0; i < n; i++) {
        vp.add(new pair(
            convertToWords(arr[i]), arr[i]));
    }

    // Sort the vector, this will sort the pair
    // according to the alphabetical order.
    Collections.sort(vp);

    // Print the sorted vector content
    for (int i = 0; i < vp.size(); i++)
        System.out.print(vp.get(i).second+ " ");
}

// Driver code
public static void main(String[] args)
{
    int arr[] = { 12, 10, 102, 31, 15 };
    int n = arr.length;

    sortArr(arr, n);
}
}

// This code is contributed by 29AjayKumar

Python3

# Python3 program to sort an array of
# integers alphabetically

# Variable to store the word form of
# units digit and up to twenty
one = [ "", "one ", "two ", "three ",
        "four ", "five ", "six ",
        "seven ", "eight ", "nine ", "ten ",
        "eleven ", "twelve ", "thirteen ",
        "fourteen ", "fifteen ", "sixteen ",
        "seventeen ", "eighteen ", "nineteen " ]

# Variable to store the word form of
# tens digit
ten = [ "", "", "twenty ",
        "thirty ", "forty ",
        "fifty ", "sixty ",
        "seventy ", "eighty ",
        "ninety " ]

# Function to convert a two digit number
# to the word by using the above defined arrays
def numToWords(n, s):

    st = ""

    # If n is more than 19, divide it
    if (n > 19):
        st += ten[n // 10] + one[n % 10]
    else:
        st += one[n]

    # If n is non-zero
    if (n):
        st += s

    return st

# Function to print a given number in words
def convertToWords(n):

    # Stores the word representation
    # of the given number n
    out = ""

    # Handles digits at ten millions
    # and hundred millions places
    out += numToWords((n // 10000000),
                      "crore ")

    # Handles digits at hundred thousands
    # and one millions places
    out += numToWords(((n // 100000) % 100),
                      "lakh ")

    # Handles digits at thousands and
    # tens thousands places
    out += numToWords(((n // 1000) % 100),
                      "thousand ")

    # Handles digit at hundreds places
    out += numToWords(((n // 100) % 10),
                      "hundred ")

    if (n > 100 and n % 100):
        out += "and "

    # Call the above function to convert
    # the number into words
    out += numToWords((n % 100), "")

    return out

# Function to sort the array according to
# the albhabetical order
def sortArr(arr, n):

    # Vector to store the number in words
    # with respective elements
    vp = []

    # Inserting number in words
    # with respective elements in vector pair
    for i in range(n):
        vp.append((convertToWords(arr[i]),
                                  arr[i]));
   
    # Sort the vector, this will sort the pair
    # according to the alphabetical order.
    vp.sort()

    # Print the sorted vector content
    for i in range(len(vp)):
        print (vp[i][1], end = " ")

# Driver code
if __name__ == "__main__":
  
    arr = [ 12, 10, 102, 31, 15 ]
    n = len(arr)

    sortArr(arr, n)

# This code is contributed by chitranayal

// C# program to sort an array of
// integers alphabetically
using System;
using System.Collections.Generic;

public class GFG{
    class pair : IComparable<pair>
    {
        public String first;
        public int second;
        public pair(String first, int second)  
        { 
            this.first = first; 
            this.second = second; 
        } 
         
        public int CompareTo(pair o)
        {
            return this.first.CompareTo(o.first);
        }
    }
  
// Variable to store the word form of
// units digit and up to twenty
static String []one
    = { "", "one ", "two ", "three ",
        "four ", "five ", "six ",
        "seven ", "eight ", "nine ", "ten ",
        "eleven ", "twelve ", "thirteen ",
        "fourteen ", "fifteen ", "sixteen ",
        "seventeen ", "eighteen ", "nineteen " };

// Variable to store the word form of
// tens digit
static String []ten
    = { "", "", "twenty ",
        "thirty ", "forty ",
        "fifty ", "sixty ",
        "seventy ", "eighty ",
        "ninety " };

// Function to convert a two digit number
// to the word by using the above defined arrays
static String numToWords(int n, String s)
{
    String str = "";

    // If n is more than 19, divide it
    if (n > 19)
        str += ten[n / 10] + one[n % 10];
    else
        str += one[n];

    // If n is non-zero
    if (n>0)
        str += s;

    return str;
}

// Function to print a given number in words
static String convertToWords(int n)
{
  
    // Stores the word representation
    // of the given number n
    String Out = "";

    // Handles digits at ten millions
    // and hundred millions places
    Out += numToWords((n / 10000000),
                      "crore ");

    // Handles digits at hundred thousands
    // and one millions places
    Out += numToWords(((n / 100000) % 100),
                      "lakh ");

    // Handles digits at thousands and
    // tens thousands places
    Out += numToWords(((n / 1000) % 100),
                      "thousand ");

    // Handles digit at hundreds places
    Out += numToWords(((n / 100) % 10),
                      "hundred ");

    if (n > 100 && n % 100!=0)
        Out += "and ";

    // Call the above function to convert
    // the number into words
    Out += numToWords((n % 100), "");

    return Out;
}

// Function to sort the array according to
// the albhabetical order
static void sortArr(int []arr, int n)
{
  
    // List to store the number in words
    // with respective elements
    List<pair> vp = new List<pair>();

    // Inserting number in words
    // with respective elements in vector pair
    for (int i = 0; i < n; i++) {
        vp.Add(new pair(
            convertToWords(arr[i]), arr[i]));
    }

    // Sort the vector, this will sort the pair
    // according to the alphabetical order.
    vp.Sort();

    // Print the sorted vector content
    for (int i = 0; i < vp.Count; i++)
        Console.Write(vp[i].second+ " ");
}

// Driver code
public static void Main(String[] args)
{
    int []arr = { 12, 10, 102, 31, 15 };
    int n = arr.Length;

    sortArr(arr, n);
}
}

// This code is contributed by shikhasingrajput

JavaScript

<script>

// JavaScript implementation of the above approach

// Variable to store the word form of
// units digit and up to twenty
var one
    = [ "", "one ", "two ", "three ",
        "four ", "five ", "six ",
        "seven ", "eight ", "nine ", "ten ",
        "eleven ", "twelve ", "thirteen ",
        "fourteen ", "fifteen ", "sixteen ",
        "seventeen ", "eighteen ", "nineteen " ];

// Variable to store the word form of
// tens digit
var ten
    = ["", "", "twenty ",
        "thirty ", "forty ",
        "fifty ", "sixty ",
        "seventy ", "eighty ",
        "ninety " ];

// Function to convert a two digit number
// to the word by using the above defined arrays
function numToWords(n, s)
{
    var str = "";

    // If n is more than 19, divide it
    if (n > 19)
        str += ten[(Math.floor(n / 10))] + one[n % 10];
    else
        str += one[n];

    // If n is non-zero
    if (n)
        str += s;

    return str;
}

// Function to print a given number in words
function convertToWords(n)
{
    // Stores the word representation
    // of the given number n
    var out;

    // Handles digits at ten millions
    // and hundred millions places
    out += numToWords(Math.floor(n / 10000000),
                      "crore ");

    // Handles digits at hundred thousands
    // and one millions places
    out += numToWords((Math.floor(n / 100000) % 100),
                      "lakh ");

    // Handles digits at thousands and
    // tens thousands places
    out += numToWords((Math.floor(n / 1000) % 100),
                      "thousand ");

    // Handles digit at hundreds places
    out += numToWords((Math.floor(n / 100) % 10),
                      "hundred ");

    if (n > 100 && n % 100)
        out += "and ";

    // Call the above function to convert
    // the number into words
    out += numToWords((n % 100), "");

    return out;
}

// Function to sort the array according to
// the albhabetical order
function sortArr(arr, n)
{
    // Vector to store the number in words
    // with respective elements
    var vp = new Array(n);

    // Inserting number in words
    // with respective elements in vector pair
    for (var i = 0; i < n; i++) {
        vp[i] = [convertToWords(arr[i]), arr[i]];
    }

    // Sort the vector, this will sort the pair
    // according to the alphabetical order.
    vp.sort();

    // Print the sorted vector content
    for (var i = 0; i < n; i++)
        document.write(vp[i][1]+" ");
}

// Driver Code
var arr = [ 12, 10, 102, 31, 15 ];
var n = arr.length;

sortArr(arr, n);

</script>

Output:

15 102 10 31 12

Time Complexity: O(N * log(N)), where N is the size of the array

Auxiliary Space: O(N)

Analysis of Algorithms

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Sort an Array alphabetically when each number is converted into words

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