Add subtraction and scalar multiplication operators to `Coordinate` and `Coordinate3d`

AdventOfCode.HelperClasses/Coordinate.cs

@@ -10,6 +10,12 @@ public record Coordinate(long X, long Y)
     
     public static Coordinate operator +(Coordinate left, Coordinate right) => 
         new(left.X + right.X, left.Y + right.Y);
+    
+    public static Coordinate operator -(Coordinate left, Coordinate right) => 
+        new(left.X - right.X, left.Y - right.Y);
+    
+    public static Coordinate operator *(Coordinate coord, int amount) => 
+        new(coord.X * amount, coord.Y * amount);
 }
 
 public record Coordinate3d(long X, long Y, long Z)
@@ -22,4 +28,10 @@ public record Coordinate3d(long X, long Y, long Z)
     
     public static Coordinate3d operator +(Coordinate3d left, Coordinate3d right) => 
         new(left.X + right.X, left.Y + right.Y, left.Z + right.Z);
+    
+    public static Coordinate3d operator -(Coordinate3d left, Coordinate3d right) => 
+        new(left.X - right.X, left.Y - right.Y, left.Z - right.Z);
+    
+    public static Coordinate3d operator *(Coordinate3d coord, int amount) => 
+        new(coord.X * amount, coord.Y * amount, coord.Z * amount);
 }

AoC_2025/Day12.cs

@@ -33,7 +33,7 @@ public class Day12 : IPuzzleSolver<long>
     private int GetMinTotalPresentArea(int[] presentCounts, int[] presentSizes)
     {
         return presentCounts
-            .Select((presentCount, index) => presentCount * presentSizes[index])
+            .Zip(presentSizes, (count, size) => count * size)
             .Sum();
     }