使用LINQ展平嵌套结构

using System;
using System.Collections.Generic;
using System.Linq;

public class Person
{
    public string Name { get; set; }
    public List<string> Hobbies { get; set; }
}

public class Program
{
    public static void Main()
    {
        List<Person> people = new List<Person>
        {
            new Person { Name = "Alice", Hobbies = new List<string> { "Reading", "Cooking" } },
            new Person { Name = "Bob", Hobbies = new List<string> { "Gardening", "Painting" } },
            new Person { Name = "Charlie", Hobbies = new List<string> { "Swimming", "Running" } }
        };

        var flattenedHobbies = people.SelectMany(person => person.Hobbies);

        foreach (var hobby in flattenedHobbies)
        {
            Console.WriteLine(hobby);
        }
    }
}