AdventOfCode2023/AdventOfCode2023/Day1/Day1_2.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace AdventOfCode2023.Day1
{
    public class Day1_2 : DayBase
    {
        string input = string.Empty;
        Regex leftSingleDigit = new Regex(@"\d|one|two|three|four|five|six|seven|eight|nine");
        Regex rightSingleDigit = new Regex(@"\d|one|two|three|four|five|six|seven|eight|nine", RegexOptions.RightToLeft);
        Dictionary<string, string> map = new Dictionary<string, string>() {
            { "one", "1" },
            { "two", "2" },
            { "three", "3" },
            { "four", "4" },
            { "five", "5" },
            { "six", "6" },
            { "seven", "7" },
            { "eight", "8" },
            { "nine", "9" },
        };

        public Day1_2()
        {
            input = GetInput("Day1.txt");
        }

        public Day1_2(string testInput)
        {
            input = testInput;
        }

        public override string Execute()
        {
            var segmentedInput = input.Split("\r\n");
            int calibrationSum = 0;

            foreach (var segment in segmentedInput)
            {
                if (!leftSingleDigit.IsMatch(segment))
                {
                    return $"segment: {segment} does not contain a digit!";
                }

                var leftMatch = leftSingleDigit.Match(segment);
                var rightMatch = rightSingleDigit.Match(segment);

                var joinedString = string.Join("", leftMatch.Value ?? "", rightMatch.Value ?? "");
                var digitizedString = joinedString;
                foreach (var item in map)
                {
                    digitizedString = digitizedString.Replace(item.Key, item.Value);
                }

                if (int.TryParse(digitizedString, out var calibrationValue))
                {
                    calibrationSum += calibrationValue;
                }
                else
                {
                    return $"Could not parse segment: {digitizedString} to int!";
                }
            }

            return calibrationSum.ToString();
        }
    }
}