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Java

Posted by Todoroki Shoto
Todoroki Shoto
301 Points

Digit Ordering in Java

I was going through some random questions and encountered one that completely stumped me. Can anyone please suggest an efficient solution for the following,

Write a function to accept an integer and return a number made up of digits from the input number in ascending order. If the input is a negative, then change the order to descending.

Example Input: 48455 Output: 44558 Input: 15243 Output: 12345 Input: -15243 Output: -54321

Todoroki Shoto
Todoroki Shoto
301 Points

This is the code I wrote and it works but I want to make use of collections or other methods to reduce the number of lines.

import java.util.*;
public class DigitOrdering {


    //Function
    public int orderDigits(int input) {
        int size;
        if(input >= 0){
            size = String.valueOf(input).length();  
        }else{
            size = String.valueOf(input).length() - 1;
        }

        int arr[] =  new int[size];
        int inputCopy = input;
        int i=0, num=0,j,temp;
        String stringNum="";
        boolean isNegative = false;
        if(inputCopy < 0){
            isNegative = true;
            inputCopy *= -1;
        }
        while(inputCopy > 0){
            arr[i++] = inputCopy % 10;
            inputCopy /= 10;
        }


        if(isNegative){
            for (i = 0; i < arr.length-1; i++){
                for (j = 0; j < arr.length-i-1; j++){
                    if (arr[j] < arr[j+1]){
                        temp = arr[j];
                        arr[j] = arr[j+1];
                        arr[j+1] = temp;
                    }
                }
            }
            for(int k: arr){
                //System.out.print(" "+k);
                stringNum += k ;    
            }
        }else{
            Arrays.sort(arr);
            for(int k: arr){
                //System.out.print(k);
                stringNum += k ;    
            }

        }
        num = Integer.parseInt(stringNum);
        //System.out.println(stringNum);
        if(isNegative){
            num *= -1;    
        }

        return num;
    }

    public void printOrderedDigits(int input) {
        System.out.println(orderDigits(input));
    }

    public static void main(String[] args) {

        if (args.length != 1) {
            System.out.println("Exactly 1 input required.");
            return;
        }
        try {
            int input = Integer.parseInt(args[0]);
            DigitOrdering obj = new DigitOrdering();
            obj.printOrderedDigits(input);
        } catch (NumberFormatException e) {
            System.out.println("Only integer allowed.");
        }
    }
}