Adv2018/D23.1/Program.cs

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

namespace D23._1
{
    class Program
    {
        static int Manhattan((int x, int y, int z, int) a, (int x, int y, int z, int) b)
        {
            return Math.Abs(a.x - b.x) + Math.Abs(a.y - b.y) + Math.Abs(a.z - b.z);
        }

        static void Main(string[] args)
        {
            if (args.Length < 1) return;
            if (File.Exists(args[0]) == false) return;

            var file = File.OpenText(args[0]);

            var reg = new Regex(@"pos=<([\d-,]+)>, r=(\d+)");

            var nanoList = new List<(int x, int y, int z, int r)>();
            (int x, int y, int z, int r) strongest = (0, 0, 0, 0);

            do
            {
                var line = file.ReadLine();
                if (line == null) break;

                var res = reg.Match(line);

                var xyz = res.Groups[1].Value.Split(",").Select(s => int.Parse(s)).ToArray();
                var r = int.Parse(res.Groups[2].Value);

                nanoList.Add((xyz[0], xyz[1], xyz[2], r));
                if (r > strongest.r) strongest = (xyz[0], xyz[1], xyz[2], r);

            } while (true);

            file.Close();

            int inRange = 0;
            foreach (var n in nanoList)
            {
                int m = Manhattan(strongest, n);
                if (m <= strongest.r) inRange += 1;
            }

            Console.WriteLine($"Answer is : {inRange}");
        }
    }
}