C# Recursive tree structure - Advent of Code 2019 Day 6

AOC 2019 - Day 6 - C# Tree Structures

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

namespace Day06
{
    class Program
    {
        static void Main(string[] args)
        {
            //Part 1
            string[] input = File.ReadAllLines(@"input.txt");
            List<OrbitObj> objList = input.Select(x => new OrbitObj { Base = x.Split(')')[0], Outer = x.Split(')')[1] }).ToList();

            Dictionary<string, List<string>> steps = new Dictionary<string, System.Collections.Generic.List<string>>();

            foreach (string outer in objList.Select(x => x.Outer))
            {
                steps.Add(outer, TotalOrbits(outer, objList, new List<string>()));
            }

            Console.WriteLine(steps.Sum(x => x.Value.Count()));

            //Part 2
            var santaSteps = TotalOrbits("SAN", objList, new List<string>());
            //steps from you down
            var youSteps = TotalOrbits("YOU", objList, new List<string>());
            //find the first step in common
            var matchStep = santaSteps.Intersect(youSteps).First();
            Console.WriteLine(santaSteps.IndexOf(matchStep) + youSteps.IndexOf(matchStep));
        }
        public static List<string> TotalOrbits(string outer, List<OrbitObj> allOrbits, List<string> currSteps)
        {
            if (outer == "COM")
            {
                return currSteps;
            }

            string currBase = allOrbits.Single(x => x.Outer == outer).Base;
            currSteps.Add(currBase);
            return TotalOrbits(currBase, allOrbits, currSteps);
        }
    }
    public class OrbitObj
    {
        public string Base { get; set; }
        public string Outer { get; set; }
    }
}