在C#中使用HashSet,与兼容

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set = new HashSet<int>();

        set.Add(1);
        set.Add(2);
        set.Add(3);

        Console.WriteLine("Contains 2: " + set.Contains(2));
        Console.WriteLine("Contains 4: " + set.Contains(4));

        HashSet<int> set2 = new HashSet<int>() { 3, 4, 5 };

        Console.WriteLine("Intersects with set2: " + set.Overlaps(set2));

        HashSet<int> unionSet = new HashSet<int>(set);
        unionSet.UnionWith(set2);

        Console.WriteLine("Union with set2:");
        foreach (int i in unionSet)
        {
            Console.WriteLine(i);
        }
    }
}