union of two set in java

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hi i need to get union of two set in java(based on set theory)
for example A={1,2,3,4,5}
B={1,2,3,6,7}
UNION:C= {1,2,3,4,5,6,7}

i coded a way but the result is wrong
plz help me!
my code:

public char[] union(char a[],char b[],int n,int m){
    int count=0;
    for(int i=0;i<a.length;i=i+2){
       for(int j=0;j<b.length;j=j+2){
       if(a[i]==b[j]){
           ++count;
       }}}
      c=new char [(n*2+m*2)-count*2];
 int j=0,h=0;
 for(int i=0;i<a.length;++i){
     c[i]=a[i];
     ++j;}
  
       for(;j<c.length;j=j+2){
           for(int i=0;i<a.length;i=i+2){
               for(int k=0;k<b.length;k=k+2){
               if(c[i]==b[k]){
                   continue;}
           else
              c[j]= b[k];  }  }
                   
   }
 return c;

Posted 27-May-11 0:28am

DominoBoy

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3 solutions

Solution 1

Why don't you make use of the Available property of java to perform the Union Operation ?

Follow the Below Steps :

* Import java.uitl.*

* Declare 2 Sets using the below methods.

 Set setName = new HashSet();
setName.add("value");

* Find the Union Using the below method

 Set unionSetName = new TreeSet(setName1);
unionSetName.addAll(setName2);

* Print the Values in the Union Set using Iterator

 Iterator it = unionSetName.iterator();
while(it.hasNext())
{
   System.out.println(in.next());
}

Take a Look at the below link for the Documentation of Set interface.
Set Interface[^]

BR//
Harsha

Posted 27-May-11 0:39am

ZeeroC00l

Updated 27-May-11 0:41am

v2

Comments

DominoBoy 27-May-11 6:42am

yeah i know but its my school work to get union of tow set without using java Set
thx any way..

Solution 2

The best way to solve this problem is to use addAll[^] method of Set<T>: add elements of a and b to HashSet<char>, then call aSet.addAll(bSet); If you need the result to be sorted, use TreeSet instead of HashSet.

P.S. Your code is grossly wrong: you are skipping odd-numbered elements for some reason (you do i = i+2 instead of i++ everywhere). If you insist on doing the union in your own code, sort both arrays before you do it: after that, you can merge everything in a single loop.

Posted 27-May-11 0:41am

dasblinkenlight

Comments

DominoBoy 27-May-11 6:44am

its my school work to get union of tow set without using java Set thx any way..
my code is for both numbers and char so how can i sort them?

dasblinkenlight 27-May-11 9:17am

Use Arrays.sort() method to sort the arrays.

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Fredrik Bornander · Accepted Answer · 2011-05-27T00:47:00

You could try something like this:

Java

public class Program {

    private static boolean contains(char[] array, char value) {
        for(char item : array) {
            if (item == value)
                return true;
        }
        return false;
    }

    public static char[] union(char[] a, char[] b) {

        List<Character> result = new ArrayList<Character>();

        for(char value : a) {
            if (contains(b, value)) {
                result.add(value);
            }
        }

        char[] resultArray = new char[result.size()];
        for(int i = 0; i < result.size(); ++i) {
            resultArray[i] = result.get(i);
        }

        return resultArray;
    }


    public static void main(String[] args) {

        char a[] = new char[] { 1, 2, 3, 4, 5};
        char b[] = new char[] { 1, 2, 3, 6, 7};

        for(char c : union(a, b)) {
            System.out.print((int)c);
        }
    }

}

/Fredrik