using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

public class Program

{

    public class SequenceComparer : IEqualityComparer<string[]>

    {

        public bool Equals(string[] x, string[] y)

        {

            if (ReferenceEquals(x, y))

                return true;

            if (x == null || y == null)

                return false;

            return x.SequenceEqual(y);

        }

​

        public int GetHashCode(string[] obj)

        {

            return obj.Aggregate(42, (c, n) => c ^ n.GetHashCode());

        }

    }

​

    public static void Main()

    {

        var json = "[\r\n    {\r\n        \"product\": [\r\n                   \"a\", \"b\", \"c\"\r\n                  ]\r\n    },\r\n    {\r\n        \"product\": [\r\n                  \"a\",\"b\"\r\n                  ]\r\n    },\r\n    {\r\n        \"product\": [\r\n                   \"b\",\"c\"\r\n                 ]\r\n    },\r\n    {\r\n       \"product\": [\r\n                   \"b\", \"c\"\r\n                ]\r\n    },\r\n    {\r\n        \"product\": [\r\n                  \"a\",\"b\"\r\n                  ]\r\n    },\r\n    {\r\n       \"product\": [\r\n                   \"b\", \"c\"\r\n                ]\r\n    },\r\n    {\r\n        \"product\": [\r\n                  \"a\"\r\n                  ]\r\n    },\r\n]";

​

​

        var products = JsonConvert.DeserializeAnonymousType(json, new[] {new {product = new string[] { }}});

        var result = products.GroupBy(p => p.product, new SequenceComparer())

            .Select(g => new {g.Key, Count = g.Count()})

            .OrderByDescending(x => x.Count)

            .Take(3);

​

        foreach (var row in result)

            Console.WriteLine("'{0}' {1}", string.Join(",", row.Key), row.Count);

​

    }

}