aoc/AdventOfCode/TwentyTwenty/Five.cs

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

namespace AoC.TwentyTwenty
{
    class Five : Day
    {
        public override int Year => 2020;
        public override int DayNumber => 5;

        public override void BigBoi(string[] input)
        {
            int grandTotal = 0;
            HashSet<int> seats = new HashSet<int>();
            
            foreach (string s in input)
            {

                int upper = 127;
                int lower = 0;
                int left = 0;
                int right = 7;

                int row = 64;
                int col = 4;
                foreach (char c in s)
                {
                    _ = c switch
                    {
                        'F' => upper -= row,
                        'B' => lower += row,
                        'L' => right -= col,
                        'R' => left += col,
                        _ => throw new Exception("AAAAAAAAAAA")
                    };

                    if (c == 'F' || c == 'B')
                    {
                        row /= 2;
                    }
                    else
                    {
                        col /= 2;
                    }
                }

                int total = (upper * 8) + left;

                if (total > grandTotal)
                {
                    grandTotal = total;
                }

                seats.Add(total);
            }

            Print("BigBoi 1", grandTotal);

            for (int i = 0; i < int.MaxValue; i++)
            {
                if (!seats.Contains(i) && seats.Contains(i + 1) && seats.Contains(i - 1))
                {
                    Print("BigBoi 2", i);
                    break;
                }
            }
        }

        public override void Part1(string[] input)
        {
            int grandTotal = 0;

            foreach (string s in input)
            {

                int upper = 127;
                int lower = 0;
                int left = 0;
                int right = 7;

                int row = 64;
                int col = 4;
                foreach (char c in s)
                {
                    _ = c switch
                    {
                        'F' => upper -= row,
                        'B' => lower += row,
                        'L' => right -= col,
                        'R' => left += col,
                        _ => throw new Exception("AAAAAAAAAAA")
                    };

                    if (c == 'F' || c == 'B')
                    {
                        row /= 2;
                    }
                    else
                    {
                        col /= 2;
                    }
                }

                int total = (upper * 8) + left;

                if (total > grandTotal)
                {
                    grandTotal = total;
                }
            }

            Print("1", grandTotal);
        }

        public override void Part2(string[] input)
        {
            HashSet<int> seats = new HashSet<int>();
            foreach (string s in input)
            {

                int upper = 127;
                int lower = 0;
                int left = 0;
                int right = 7;

                int row = 64;
                int col = 4;
                foreach (char c in s)
                {
                    _ = c switch
                    {
                        'F' => upper -= row,
                        'B' => lower += row,
                        'L' => right -= col,
                        'R' => left += col,
                        _ => throw new Exception("AAAAAAAAAAA")
                    };

                    if (c == 'F' || c == 'B')
                    {
                        row /= 2;
                    }
                    else
                    {
                        col /= 2;
                    }
                }

                seats.Add((upper * 8) + left);
            }

            for (int i = 0; i < 1028; i++)
            {
                if (!seats.Contains(i) && seats.Contains(i + 1) && seats.Contains(i - 1))
                {
                    Print("2", i);
                    break;
                }
            }
        }
    }
}