Files

Files.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

class Files
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine());

        List<string> allFiles = new List<string>();
        for (int i = 0; i < n; i++)
        {
            allFiles.Add(Console.ReadLine());
        }

        string filter = Console.ReadLine();
        var filterTokens = Regex.Split(filter, " in ");
        var filterExt = "." + filterTokens[0];
        var filterRoot = filterTokens[1] + @"\";

        var fileSize = new Dictionary<string, int>();
        foreach (var f in allFiles)
        {
            var filePlusSize = f.Split(';');
            var size = int.Parse(filePlusSize[1]);
            var path = filePlusSize[0];
            if (path.StartsWith(filterRoot) && path.EndsWith(filterExt))
            {
                var tokens = path.Split('\\');
                var fileName = tokens[tokens.Length - 1];
                fileSize[fileName] = size;
            }
        }

        var sortedOutputFiles = 
            fileSize.OrderByDescending(fs => fs.Value)
            .ThenBy(fs => fs.Key);

        foreach (var file in sortedOutputFiles)
        {
            Console.WriteLine(file.Key + " - " + file.Value + " KB");
        }

        if (sortedOutputFiles.Count() == 0)
            Console.WriteLine("No");
    }
}