用Set实现数学集合的交并差，交集外所有的元素

import javafx.animation.SequentialTransition;

import java.util.*;

public class Sets {
    //求并集
    public static  Set union(Set a, Set b) {
        Set result = new HashSet(a);
        result.addAll(b);
        return result;
    }

    //求交集
    public static  Set intersection(Set a, Set b) {
        Set result = new HashSet(a);
        result.retainAll(b);
        return result;

    }

    //求差集
    public static  Set difference(Set a, Set b) {
        Set result = new HashSet<>(a);
        result.removeAll(b);
        return result;
    }

    //求交集外所有元素
    public static  Set complement(Set a, Set b) {
        return difference(union(a,b),intersection(a,b));

    }

}