Day 1 Advent of Code 2020

aoc2020-01.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using AdventOfCode.Library;

namespace AdventOfCode
{
    //    Day 01
    internal static class Program
    {
        private static bool _doPart1 = true;
        private static bool _doPart2 = true;

        public static void Main()
        {
            //    Process your data here
            var data = TextUtility.ReadLines(removeBlank: true);
            var finalData = data.ToList();

            //    Get ready to track everything
            var watch1 = new Stopwatch();
            var watch2 = new Stopwatch();
            var answer1 = "";
            var answer2 = "";

            //    Solve problems.
            if (_doPart1)
            {
                watch1.Start();
                answer1 = Part1(finalData);
                watch1.Stop();
            }

            if (_doPart2)
            {
                watch2.Start();
                answer2 = Part2(finalData);
                watch2.Stop();
            }

            //    Do output
            if (!string.IsNullOrEmpty(answer1) || !string.IsNullOrEmpty(answer2))
            {
                Console.WriteLine("Results");
                if (_doPart1)
                {
                    Console.WriteLine($"PART 1 ANSWER:\t{answer1}\n{watch1.ElapsedMilliseconds} ms");
                }

                if (_doPart2)
                {
                    Console.WriteLine($"PART 2 ANSWER:\t{answer2}\n{watch2.ElapsedMilliseconds} ms");
                }
            }
            else
            {
                Console.WriteLine("No results have been activated.");
            }
        }

        private static string Part1(IEnumerable<string> data)
        {
            var numbers = data.Select(long.Parse).ToList();
            const long baseValue = 2020;

            foreach (long index in numbers.Where(idx => numbers.Contains(baseValue - idx)))
            {
                return (index * (baseValue - index)).ToString();
            }

            return "-1";
        }

        // ReSharper disable once UnusedParameter.Local
        // ReSharper disable once UnusedMember.Local
        private static string Part2(IEnumerable<string> data)
        {
            var numbers = data.Select(long.Parse).ToList();
            const long baseValue = 2020;
            
            foreach (long index1 in numbers)
            {
                long temp = baseValue - index1;
                foreach (long index2 in numbers.Where(index => index != index1))
                {
                    if (numbers.Contains(temp - index2))
                    {
                        return (index1 * (temp - index2) * index2).ToString();
                    }
                }
            }

            return "-1";
        }
    }
}