fork(2) download
copy 
  1. import java.util.ArrayList;
  2. class PowerSet
  3. {
  4.     public static ArrayList<String> getpowerset(int a[],int n,ArrayList<String> ps)
  5.     {
  6.         if(n<0)
  7.         {
  8.             return null;
  9.         }
  10.         if(n==0)
  11.         {
  12.             if(ps==null)
  13.                 ps=new ArrayList();
  14.             ps.add(" ");
  15.             return ps;
  16.         }
  17.         ps=getpowerset(a, n-1, ps);
  18.         ArrayList<String> tmp=new ArrayList<String>();
  19.         for(String s:ps)
  20.         {
  21.             if(s.equals(" "))
  22.                 tmp.add(""+a[n-1]);
  23.             else
  24.                 tmp.add(s+a[n-1]);
  25.         }
  26.         ps.addAll(tmp);
  27.         return ps;
  28.     }
  29.     public static void main(String[] ar)
  30.     {
  31.     	int a[]={1,2,3,4};
  32.         int n=a.length;
  33.         ArrayList<String> subset=PowerSet.getpowerset(a, n, new ArrayList<String>());
  34.  
  35.         for(String s:subset)
  36.             System.out.println("{"+s+"}");
  37.     }
  38. }
  39.  
stdin
copy 
Standard input is empty
compilation info 
Note: Main.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
stdout
copy 
{ }
{1}
{2}
{12}
{3}
{13}
{23}
{123}
{4}
{14}
{24}
{124}
{34}
{134}
{234}
{1234}
https://ideone.com/w14kV
language:
Java (HotSpot 12)
created:
14 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!