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  1. import java.util.HashSet;
  2.  
  3. final class Connection {
  4.     public final int A;
  5.     public final int B;
  6.  
  7.     public Connection(final int a, final int b) {
  8.         if (a == b)
  9.             throw new IllegalArgumentException("points must be different");
  10.         A = a;
  11.         B = b;
  12.     }
  13.  
  14.     @Override
  15.     public boolean equals(Object o) {
  16.         if (this == o) return true;
  17.         if (o == null || getClass() != o.getClass()) return false;
  18.  
  19.         Connection that = (Connection) o;
  20.  
  21.         return (A == that.A && B == that.B || A == that.B && B == that.A);
  22.     }
  23.  
  24.     @Override
  25.     public int hashCode() {
  26.         return A ^ B;
  27.     }
  28.  
  29.     @Override
  30.     public String toString() {
  31.         return "Connection{" +
  32.                 "A=" + A +
  33.                 ", B=" + B +
  34.                 '}';
  35.     }
  36. }
  37.  
  38.  
  39. class Ideone {
  40.     public static void main(String[] args) throws java.lang.Exception {
  41.         HashSet<Connection> s = new HashSet<>();
  42.         s.add(new Connection(1, 3));
  43.         s.add(new Connection(2, 3));
  44.         s.add(new Connection(3, 2));
  45.         s.add(new Connection(1, 3));
  46.         s.add(new Connection(2, 1));
  47.  
  48.         s.remove(new Connection(1, 2));
  49.  
  50.         for (Connection x : s) {
  51.             System.out.println(x);
  52.         }
  53.  
  54.         // output:
  55.         // Connection{A=2, B=3}
  56.         // Connection{A=1, B=3}
  57.     }
  58. }
Success #stdin #stdout 0.07s 380160KB
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Connection{A=2, B=3}
Connection{A=1, B=3}
https://ideone.com/znGOJR
language:
Java (12.0.1)
created:
10 years ago
visibility:
public

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