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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12. 		System.out.println(helfer(new String[]{"A", "u", "D"}, 0));
  13. 	}
  14. 	static <T> List<List<T>> helfer(T[] s, int idx) {
  15. 	// Rückgabe pms ist Potenzmenge von s ab index idx
  16. 	List<List<T>> pms = new ArrayList<List<T>>();
  17. 	if (idx >= s.length) {
  18. 		// Basisfall
  19. 		pms.add(new ArrayList<T>());
  20. 	} else {
  21. 		// aktuelles Kopfelement bestimmen
  22. 		T kopf = s[idx];
  23.  
  24. 		// Potenzmenge der Restliste bestimmen
  25. 		List<List<T>> potRest = helfer(s, idx + 1);
  26.  
  27. 		// Ergebnisse zusammenführen
  28. 		for (List<T> ohneKopf : potRest) {
  29. 			List<T> mitKopf = new ArrayList<>(ohneKopf); // *nocH* ohne Kopf
  30. 			mitKopf.add(kopf);
  31.  
  32. 			pms.add(ohneKopf);
  33. 			pms.add(mitKopf);
  34. 		}
  35. 	}
  36. 	return pms;
  37. }
  38. }
Success #stdin #stdout 0.1s 320576KB
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Standard input is empty
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[[], [A], [u], [u, A], [D], [D, A], [D, u], [D, u, A]]
https://ideone.com/jr02d3
language:
Java (12.0.1)
created:
8 years ago
visibility:
public

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