Ghost Legs - coding games

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

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 **/
class Solution
{
    static void Main(string[] args)
    {
        string[] inputs = Console.ReadLine().Split(' ');
        int W = int.Parse(inputs[0]);
        int H = int.Parse(inputs[1]);

        string[] header = null;
        string[] footer = null;
        string[] result = null;
        // column
        int k = 0; // resting column
        int headerIndex = 0; // starting column

        var lines = new string[H];

        // read all lines
        for (int i = 0; i < H; i++)
        {
            lines[i] = Console.ReadLine();
            Console.Error.WriteLine(lines[i]);
        }

        int letterColumns = lines[0].Split(' ', StringSplitOptions.RemoveEmptyEntries).Length;

        // for each column
        for (int j = 0; j < letterColumns; j++)
        {
            headerIndex = j; // starting column, this will be used later to retrive the header e.g: A, B, C
            k = j; // will be used alter to retrive the resting position. e.g: 1,2,3

            // headerIndex = 1;
            // k = 1;
            for (int i = 0; i < H; i++)
            {
                string line = lines[i];

                // read header
                if (i == 0)
                {
                    header ??= line.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                }
                // reader footer
                else if (i + 1 == H)
                {
                    // read footer
                    footer = line.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                    result ??= new String[header.Length];
                    result[headerIndex] = header[headerIndex] + footer[k];
                }
                // read body
                else
                {
                    // var parts = line.Split('|', StringSplitOptions.RemoveEmptyEntries);
                    var parts = line.Split('|')

/*
                    if (k == 0 && parts[0] == "--")
                    {
                        k++;
                    }*/
                    if (k - 1 >= 0 && parts[k] == "--")
                    {
                        k--;
                    }
                    else if (k + 1 < letterColumns && parts[k + 1] == "--")
                    {
                        k++;
                    }
                    else if (k + 1 == letterColumns && parts[k] == "--")
                    {
                        k--;
                    }
                }
            }
        }


        // Write an answer using Console.WriteLine()
        // To debug: Console.Error.WriteLine("Debug messages...");
        Console.WriteLine(string.Join(Environment.NewLine, result).Trim());
    }
}

// game: https://www.codingame.com/ide/puzzle/ghost-legs