AdventOfCode/StringExtensions.cs

namespace AdventOfCode;

public static class StringExtensions
{
    public static IEnumerable<string> ReadAllLines(this StringReader reader)
    {
        while (reader.ReadLine() is { } line)
        {
            yield return line;
        }
    }

    public static IEnumerable<string> ReadAllLines(this string text)
    {
        return new StringReader(text).ReadAllLines();
    }

    public static char[,] AsCharGrid(this string text)
    {
        var lines = text.ReadAllLines().ToArray();
        var lineCount = lines.Length;
        var columnCount = lines[0].Length;

        var grid = new char[lineCount, columnCount];

        for (int i = 0; i < lineCount; i++)
        {
            var line = lines[i];

            for (int j = 0; j < columnCount; j++)
            {
                grid[i, j] = line[j];
            }
        }

        return grid;
    }
}