Simple Algorithm

[coin-god]

So I have a number, I have to make a function that gets this number and returns a new number in wich it's digits are sorted from highest to lowest (and second version doing lowest to highest).

I'm having a hard time thinking about how to do it.

 

For example 52513 would return 55321.

 

I've already wrote something, but imo it's to ugly and long. (And dosn't work, stopped working on it)

Could anyone help me? (It's for JAVA)

[Andrew]

You're after a simple sorting algorithm, http://www.sorting-algorithms.com/ has 8 of the more common ones it also lists the peusdocode which should help you.

 

 

[coin-god]

I still havn't learn how to use arrays. The site looks awesome, but it's confusing me even more.

[Swoorup]

Here's the VB6 code. Hope you can translate this to >> java man

 

BTW I used the insertion sort method cause its easier and faster when working with large numbers!

 

VB6 functions:

 

Mid(string, <starting pos> , <number of characters>

Used to store string from the middle of a string

 

Val(string)

Used to convert a string to number

 

Dim <variable> AS <data type>

Declare a variable as data type

 

Swap a(i),a(j)

Interchange the position of values

 

len

Count the number of characters in a string

 

 

Dim a{len(string)} as Integer'Take individual numbers to arrayFor i= 1 to len(string) a(i)= mid{string,i,1}next i'A number Checks numbers before it and it is swapped if it bigger than the other'So basically to check numbers before we have to start from 2nd valuefor i = 2 to len (string) For j= 1 to i - 1   If val{a(i)} < val{a(j)} then      For k = j to i-1         swap a(i), a(j)      next k      Exit for   End if Next jNext i'Combine the array into the stringfor I= 1 to len(strin) string= string+a(i)next i

 

 

EDIT: OOPs I am sorry, use asc instead of Val, asc turns the character into ascii code

Edited September 11, 2011 by Swoorup

[Andrew]

If you post what you've got so far, we can help you improve your code and point you in the right direction.

 

Whilst this isn't Java it is C#, but the syntax of the two languages are practically the same.

 

First is to convert a number string into an array of ints

 

//get length of inputint strLen = input.Length;int[] numbers = new int[strLen]; //define array of input length//loop through the input array//converting chars to ints//place into numbers arrayfor (int i = 0; i < strLen; i++)    {          numbers[i] = int.Parse(input[i].ToString());     }            

 

 

The insertion sort method is like so.

(taken from here: http://www.publicjoe.f9.co.uk/csharp/sort03.html)

 

 

//takes numbers array and array sizepublic static int[] sort(int[] array, int arrayLen)       {           int i;           int j;           int index;           for (i = 1; i < arrayLen; i++)           {               index = array[i];               j = i;               while ((j > 0) && (array[j - 1] < index)) //swap < for > to reverse               {                   array[j] = array[j - 1];                   j = j - 1;               }               array[j] = index;           }           return array;       }