2022 day 7 part 1 works for test input??

AOC.Common/DefaultDictionary.cs

@@ -0,0 +1,16 @@
+namespace AOC.Common;
+
+public class DefaultDictionary<TKey, TValue> : Dictionary<TKey, TValue> where TValue : new() where TKey : notnull
+{
+    public new TValue this[TKey key]
+    {
+        get
+        {
+            if (TryGetValue(key, out var val)) return val;
+            val = new();
+            Add(key, val);
+            return val;
+        }
+        set => base[key] = value;
+    }
+}

AOC2022/Day07.cs

@@ -5,23 +5,41 @@ namespace AOC2022;
 /// </summary>
 public sealed class Day07 : Day
 {
+    private readonly DefaultDictionary<string, long> _dirs;
+
     public Day07() : base(2022, 7, "No Space Left On Device")
     {
-    }
-
-    public override object Part1()
-    {
-        var dirs = new Dictionary<string, long>();
+        _dirs = new();
+        var path = new Stack<string>();
         foreach (var line in Input)
         {
-            if (line.StartsWith('$'))
+            if (line.StartsWith("$ cd"))
             {
-                // command
+                var split = line.Split("$ cd ");
+                if (split[1] == "..")
+                {
+                    path.Pop();
+                }
+                else if (split[1] != "/")
+                {
+                    path.Push(split[1]);
+                }
+            }
+            else
+            {
+                if (!long.TryParse(line.Split(' ')[0], out var filesize))
+                    continue;
                 
+                var pathList = path.ToList();
+
+                foreach (var i in Enumerable.Range(0, path.Count + 1))
+                    _dirs[string.Join("/", pathList.GetRange(0, i))] += filesize;
             }
         }
-
     }
 
+    public override object Part1() =>
+        _dirs.Values.Where(d => d <= 1_000_000L).Sum();
+
     public override object Part2() => "";
 }