import java.util.HashSet;
import java.util.Set;
class Pair
{
public int x, y;
Pair(int x, int y) {
this.x = x;
this.y = y;
}
}
public class MyClass
{
public static void findPairs(Pair[] pairs) {
Set<String> set = new HashSet<>();
for (Pair one_pair: pairs) {
String onepair = "(" + one_pair.x + ", " + one_pair.y + ")";
set.add(onepair);
String reverse_onepair = "(" + one_pair.y + ", " + one_pair.x + ")";
if (set.contains(reverse_onepair)) {
System.out.println(onepair + " - " + reverse_onepair);
}
}
}
public static void main(String[] args)
{
Pair[] pairs = {
new Pair(7, 2), new Pair(1, 8), new Pair(4, 6), new Pair(5, 1),
new Pair(9, 3), new Pair(2, 7), new Pair(1, 5)
};
findPairs(pairs);
}
}
/*
run:
(2, 7) - (7, 2)
(1, 5) - (5, 1)
*/