Character Array Question in Core Java

[Deepak Lal]

Ranchers,


Given two character arrays a[] and b[], remove from b[],all occurrences of all characters that occur in array a[]. You need to do this in-place i.e. without using an extra array of characters. E.g.:

Input: a[] = ['G', 'O']
Input b[] = ['G', 'O', 'O', 'G', 'L', 'E']

Output: b[] = ['L', 'E']

PS:I dont want to use an EXTRA Array for this,How do i accomplish this ? Please help ranchers

[Kevin Workman]

That's not really how this works. What have you tried? Where are you stuck? Feel free to post some code, in SSCCE form, for us to work off of.

PS- Your all-bold text makes my eyes sad.

[Deepak Lal]

   public class ReplaceCharacterArray{          
       public static void main(String args[]){         
          char a[] = {'G', 'O'}          
          char b[] = {'G', 'O', 'O', 'G', 'L', 'E'}      
 
         //to replace all the occurences of all the characters of      
         //a[] array in b[] array we have below logic.      
 
          for(int i=0;i<a.length;i++){      
             for(int j=0;j<b.length;j++){      
                  if(b[j] == a[i]){      
                    //im stuck here how to proceed      //i do not want to append b[] array with Null Characters. 
                   //i dont want to do b[j] = null here....any other approach suggest me.
             }      
          }    
    

[Kevin Workman]

If you don't want to use another array, and you don't want empty array positions, what do you think your other options are? You could shift everything down an index, but then you'd still have empty array positions at the end of the array. Are you sure you're understanding your requirements correctly?

[Deepak Lal]

This is requirement
1> No empty Array Positions after returning the Array
2> Dont use an extra Array for your operation.

This is what the question says clearly.This was asked by interviewer himself and he said there exists a solution but when i asked him,he asked me to try it for myself.

[Kevin Workman]

Ah, then perhaps he wants you to use the Collections and Arrays classes?

http://download.oracle.com/javase/6/docs/api/java/util/Arrays.html
http://download.oracle.com/javase/6/docs/api/java/util/Collections.html

[Wouter Oet]

And some of them use an array internally

[Deepak Lal]

Ranchers,Could you let me know about the solution.

[Rob Spoor]

There is no solution with these requirements. You want to go from a 6-element array to a 2-element array without creating a new array or having empty positions. That's simply not possible.