using System;           

using System.Collections.Generic;

using System.Linq;

​

class Recipe

{

    public string Name { get; set; }

}

​

class Ingredient {

    public string Name { get; set; }

}

​

class User {

    public string Name { get; set; }

}

​

class User_ing

{

    public User user { get; set; }

    public Ingredient ing { get; set; }

}

​

class Recipe_ing {

    public Recipe recipe { get; set; }

    public Ingredient ing { get; set; }

}

​

​

​

​

public class Program

{

    public static void Main()

    {

        User shai = new User { Name = "Gidon" };

        User ali = new User { Name = "ניסיתי ככה" };

        Recipe pasta = new Recipe { Name = "pasta" };

        Recipe pizza = new Recipe { Name = "pizza" };

        Recipe burger = new Recipe { Name = "burger" };

        Ingredient noodles = new Ingredient { Name = "noodles" };

        Ingredient cheese = new Ingredient { Name = "cheese" };

        Ingredient pepperoni = new Ingredient { Name = "cow #743875287" };

        Ingredient buns = new Ingredient { Name = "buns" };

        Ingredient sheep = new Ingredient { Name = "sheep" };

        List<User_ing> user_ingredients = new List<User_ing> {

            new User_ing { user = ali, ing = cheese },

            new User_ing { user = ali, ing = pepperoni },

            new User_ing { user = ali, ing = noodles },

            new User_ing { user = ali, ing = sheep }

        };

        List<Recipe_ing> recipe_ingredients = new List<Recipe_ing> { 

            new Recipe_ing { recipe = pasta, ing = noodles },

            new Recipe_ing { recipe = pizza, ing = cheese },

            new Recipe_ing { recipe = pizza, ing = pepperoni },

            new Recipe_ing { recipe = burger, ing = buns },

            new Recipe_ing { recipe = burger, ing = sheep }

        };

        var query = recipe_ingredients.Join(

            user_ingredients.Where(ing => ing.user == ali),

            ing => ing.ing,

            ing => ing.ing,

            (recipe_ing, user_ing) => recipe_ing.recipe

        ).Distinct();

        Console.WriteLine("Ali's potential recipes:\n");

​

        foreach (var obj in query)

        {

            Console.WriteLine(

                "{0}",

                obj.Name);

        }

    }

}