A solution for challenge #221 from /r/dailyprogrammer

PoemFinder.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;

namespace PoemFinder
{
  internal static class PoemFinder
  {
    private static void Main(string[] args)
    {
      const string wordListUrl = "http://www-01.sil.org/linguistics/wordlists/english/wordlist/wordsEn.txt";
      // a hash-based list containing only distinct, lower-cased words with three or more letters
      var wordList = ReadLines(() => new WebClient().OpenRead(wordListUrl));
      var uniqueWordList =
          new HashSet<string>(wordList.Where(w => w.Length > 2).Select(w => w.ToLower()));

      const string challengeInputUrl = "https://gist.githubusercontent.com/anonymous/c8fb349e9ae4fcb40cb5/raw/05a1ef03626057e1b57b5bbdddc4c2373ce4b465/challenge.txt";
      var challengeInputLines = ReadLines(() => new WebClient().OpenRead(challengeInputUrl));

      var challengeOutputLines = challengeInputLines.Where(line =>
      {
        // A list of the lower-cased version of all words with three or more letters in the line
        var candidateWordList = line.Split(' ').Where(w => w.Length > 2).Select(w => w.ToLower()).ToList();
        var candidateWordCount = candidateWordList.Count();

        // count all of the words in the line which are also in uniqueWordList
        var hitCount = candidateWordList.Where(word => uniqueWordList.Contains(word)).ToList().Count;

        // if the ratio of hits to words is high enough...
        return (float) hitCount/candidateWordCount > .7;
      });

      challengeOutputLines.ToList().ForEach(line => Console.WriteLine(line));
    }

    // Thanks JonSkeet: http://stackoverflow.com/a/13312954/12604
    private static IEnumerable<string> ReadLines(Func<Stream> streamProvider)
    {
      using (var stream = streamProvider())
      using (var reader = new StreamReader(stream, Encoding.UTF8))
      {
        string line;
        while ((line = reader.ReadLine()) != null)
        {
          yield return line;
        }
      }
    }
  }
}