Adv2016/D20.1/Program.cs

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

namespace D20._1
{
    public class R : StreamReader, IEnumerable
    {
        public R(Stream stream) : base(stream) { }
        public IEnumerator GetEnumerator()
        {
            while (true)
            {
                var line = ReadLine();
                if (line == null) break;
                yield return line;
            }
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var ranges = new List<(uint start, uint end)>();
            using (var file = new R(File.OpenText(args[0]).BaseStream))
            {
                foreach (string line in file)
                {
                    var lr = line.Split("-");
                    var start = uint.Parse(lr[0]);
                    var end = uint.Parse(lr[1]);

                    ranges.Add((start, end));
                }
            }

            ranges.Sort();

            uint smallest = 0;
            while (ranges.Count > 0)
            {
                var (start, end) = ranges.ElementAt(0);
                ranges.RemoveAt(0);

                if (smallest >= start && smallest <= end)
                    smallest = end + 1;
            }

            Console.WriteLine($"The answer is : {smallest}");
        }
    }
}