Add day 7

Days/Day5.cs

@@ -14,26 +14,25 @@ public class Day5 : Day
         var precedences = new HashSet<int>?[100];
 
         var readingPrecedences = true;
-        foreach (var line in Input.ReadAllLines())
+        foreach (var line in Input.AsSpan().EnumerateLines())
         {
-            if (string.IsNullOrWhiteSpace(line))
+            if (line.IsWhiteSpace())
             {
                 readingPrecedences = false;
 
                 continue;
             }
 
-            var span = line.AsSpan();
             if (readingPrecedences)
             {
-                var split = span.Split('|');
+                var split = line.Split('|');
                 split.MoveNext();
 
-                var ruleTarget = int.Parse(span[split.Current]);
+                var ruleTarget = int.Parse(line[split.Current]);
 
                 split.MoveNext();
 
-                var ruleNumber = int.Parse(span[split.Current]);
+                var ruleNumber = int.Parse(line[split.Current]);
 
                 if (precedences[ruleTarget] is not { } precedenceSet)
                 {
@@ -47,7 +46,7 @@ public class Day5 : Day
             }
             else
             {
-                result += CheckLine(span);
+                result += CheckLine(line);
             }
         }