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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. class Nested<A> {
  8. 	public A left;
  9. 	public Nested<List<A>> right;
  10. 	public Nested(A l, Nested<List<A>> r) {
  11. 		left = l;
  12. 		right = r;
  13. 	}
  14. }
  15.  
  16. class Ideone
  17. {
  18. 	static <A> int length(Nested<A> xs) {
  19. 		if (xs == null) {
  20. 			return 0;
  21. 		} else {
  22. 			return 1 + length(xs.right);
  23. 		}
  24. 	}
  25. 	public static void main (String[] args) throws java.lang.Exception
  26. 	{
  27. 		List<Integer> l234 = Arrays.asList(2, 3, 4);
  28. 		List<Integer> l56 = Arrays.asList(5, 6);
  29. 		List<Integer> l7 = Arrays.asList(7);
  30. 		List<List<Integer>> l567 = Arrays.asList(l56, l7);
  31. 		Nested<Integer> nested =
  32. 			new Nested(
  33. 				1,
  34. 				new Nested(
  35. 					l234,
  36. 					new Nested(
  37. 						l567,
  38. 						null
  39. 					)
  40. 				)
  41. 			);
  42. 		System.out.println(length(nested));
  43. 	}
  44. }
Success #stdin #stdout 0.07s 380160KB
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stdout 
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https://ideone.com/cTbi1m
language:
Java (12.0.1)
created:
10 years ago
visibility:
public

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