using System;

using System.Collections.Generic;

public class Program

{

    //ProductAttribute

    //Size - Id 1

    //Color - Id 2

    //ProductAttributeValue

    //S - Id 1, FK 1

    //M - Id 2, FK 1

    //Black - Id 3, FK 2

    //White -Id 4, FK 2

    //Red - Id 5, FK 2

    //Expected output:

    //[S - Black], [1, 3]

    //[S - White], [1, 4]

    //[S - Red], [1, 5]

    //[M - Black], [2, 3]

    //[M - White], [2, 4]

    //[M - Red], [2, 5]

    public class CombinedValuePair {

        public string CombinationText { get; set; }

        public string CombinationValue { get; set; }

    }

    public class ProductAttribute {

        public int idProductAttribute { get; set; }

        public string displayText { get; set; }

    }

    public class ProductAttributeValue {

        public int idProductAttributeValue { get; set; }

        public int idProductAttribute { get; set; }

        public string displayText { get; set; }

    }

    public static void Main()

    {

        var productAttributeList = new List<ProductAttribute>();

        productAttributeList.Add(new ProductAttribute {

            idProductAttribute = 1,

            displayText = "Size"

        });

        productAttributeList.Add(new ProductAttribute {

            idProductAttribute = 2,

            displayText = "Color"

        });

        var productAttributeValueList = new List<ProductAttributeValue>();

        productAttributeValueList.Add(new ProductAttributeValue {

            idProductAttributeValue = 1,

            idProductAttribute = 1,

            displayText = "S"

        });

        productAttributeValueList.Add(new ProductAttributeValue {

            idProductAttributeValue = 2,

            idProductAttribute = 1,

            displayText = "M"

        });

        productAttributeValueList.Add(new ProductAttributeValue {

            idProductAttributeValue = 3,

            idProductAttribute = 2,

            displayText = "Black"

        });

        productAttributeValueList.Add(new ProductAttributeValue {

            idProductAttributeValue = 4,

            idProductAttribute = 2,

            displayText = "White"

        });

        productAttributeValueList.Add(new ProductAttributeValue {

            idProductAttributeValue = 5,

            idProductAttribute = 2,

            displayText = "Red"

        });

        //Question: User choose ProductAttribute [Size] & [Color], system shall return a new list of combination based on ProductAttributeValue.

        //Expected output:

        //[S - Black], [1, 3]

        //[S - White], [1, 4]

        //[S - Red], [1, 5]

        //[M - Black], [2, 3]

        //[M - White], [2, 4]

        //[M - Red], [2, 5]

        //write your code below

        var combinedValuePairList = new List<CombinedValuePair>();                     

        var sizeAttributeList = productAttributeValueList.FindAll(a => a.idProductAttribute == 1);

        var colorAttributeList = productAttributeValueList.FindAll(a => a.idProductAttribute == 2);

​

        foreach (var s in sizeAttributeList)

            foreach(var c in colorAttributeList)

            {

                combinedValuePairList.Add(new CombinedValuePair

                {

                    CombinationText = String.Format("{0} - {1}", s.displayText, c.displayText),

                    CombinationValue = String.Format("{0}, {1}", s.idProductAttributeValue, c.idProductAttributeValue)

                });

​

            }

​

        foreach (var c in combinedValuePairList)

            Console.WriteLine("[{0}], [{1}]", c.CombinationText, c.CombinationValue);

    }

}