day 13 part 2

KaterynaKateryna · Dec 13, 2023 · 9afe9f1 · 9afe9f1
1 parent b4618fb
commit 9afe9f1
Showing 1 changed file with 38 additions and 19 deletions.
diff --git a/AdventOfCode/Day13.cs b/AdventOfCode/Day13.cs
@@ -14,23 +14,34 @@ public Day13()
     }
 
     public override ValueTask<string> Solve_1()
+    {
+        int sum = Solve(0);
+        return new(sum.ToString());
+    }
+
+    public override ValueTask<string> Solve_2()
+    {
+        int sum = Solve(1);
+        return new(sum.ToString());
+    }
+
+    private int Solve(int expectedSmudges)
     {
         int sum = 0;
         for (int i = 0; i < _input.Length; ++i)
         {
-            sum += GetMirror(_input[i], Direction.Vertical);
-            sum += GetMirror(_input[i], Direction.Horizontal) * 100;
+            sum += GetMirror(_input[i], Direction.Vertical, expectedSmudges);
+            sum += GetMirror(_input[i], Direction.Horizontal, expectedSmudges) * 100;
         }
-
-        return new(sum.ToString());
+        return sum;
     }
 
-    private int GetMirror(string[] pattern, Direction direction)
+    private int GetMirror(string[] pattern, Direction direction, int expectedSmudges)
     {
         int length = direction == Direction.Vertical ? pattern[0].Length : pattern.Length;
         for (int i = 0; i < length - 1; ++i)
         {
-            if (IsMirror(pattern, i, direction, length))
+            if (IsMirror(pattern, i, direction, length, expectedSmudges))
             {
                 return i + 1;
             }
@@ -39,43 +50,51 @@ private int GetMirror(string[] pattern, Direction direction)
         return 0;
     }
 
-    private bool IsMirror(string[] pattern, int splitAfter, Direction direction, int length)
+    private bool IsMirror(string[] pattern, int splitAfter, Direction direction, int length, int expectedSmudges)
     {
         int a = splitAfter;
         int b = splitAfter + 1;
 
+        int smudges = 0;
+
         while (a >= 0 && b < length)
         {
-            if (!(direction == Direction.Vertical ? ColumnsEqual(pattern, a, b) : RowEqual(pattern, a, b)))
+            smudges += direction == Direction.Vertical ? ColumnsSmudges(pattern, a, b) : RowSmudges(pattern, a, b);
+            if (smudges > expectedSmudges)
             { 
                 return false;
             }
             a--;
             b++;
         }
-        return true;
+        return smudges == expectedSmudges;
     }
 
-    private bool ColumnsEqual(string[] pattern, int a, int b)
+    private int ColumnsSmudges(string[] pattern, int a, int b)
     {
+        int smudges = 0;
         for (int i = 0; i < pattern.Length; ++i)
         {
             if (pattern[i][a] != pattern[i][b])
-            { 
-                return false;
+            {
+                smudges++;
             }
         }
-        return true;
+        return smudges;
     }
 
-    private bool RowEqual(string[] pattern, int a, int b)
+    private int RowSmudges(string[] pattern, int a, int b)
     {
-        return pattern[a] == pattern[b];
-    }
+        int smudges = 0;
+        for (int i = 0; i < pattern[0].Length; ++i)
+        {
+            if (pattern[a][i] != pattern[b][i])
+            {
+                smudges++;
+            }
+        }
 
-    public override ValueTask<string> Solve_2()
-    {
-        return new("TBD");
+        return smudges;
     }
 
     private enum Direction