Add AoC 2024 day 12 part 1 solver

assets/advent_of_code/2024_12_sample.txt

@@ -0,0 +1,10 @@
+RRRRIICCFF
+RRRRIICCCF
+VVRRRCCFFF
+VVRCCCJFFF
+VVVVCJJCFE
+VVIVCCJJEE
+VVIIICJJEE
+MIIIIIJJEE
+MIIISIJEEE
+MMMISSJEEE

lib/solvers/advent_of_code/2024/_all_solvers.dart

@@ -5,3 +5,4 @@ export 'day_04_solver.dart';
 export 'day_05_solver.dart';
 export 'day_06_solver.dart';
 export 'day_11_solver.dart';
+export 'day_12_solver.dart';

lib/solvers/advent_of_code/2024/day_12_solver.dart

@@ -0,0 +1,50 @@
+import 'package:h3x_devtools/solvers/advent_of_code/2024/aoc_2024_solver.dart';
+
+class Day12Solver extends AdventOfCode2024Solver {
+
+  @override
+  final int dayNumber = 12;
+
+  @override
+  String getSolution(String input) {
+    Grid<String> grid = Grid.fromString(input, (value) => value);
+
+    // Part 1
+    Map<String, int> areaSizes = {}, perimeterLengths = {};
+    int currentAreaNameChar = 97;
+    for (int x = 0; x < grid.width; x++) {
+      for (int y = 0; y < grid.height; y++) {
+        Coordinates coordinates = Coordinates(x, y, grid);
+        Cell<String> cell = grid[coordinates];
+
+        // Area size
+        if (!areaSizes.containsKey(cell.obj)) {
+          // Because some area names can be used for multiple areas, make the area names unique.
+          grid.floodFill4Way(coordinates, cell.obj, String.fromCharCode(currentAreaNameChar));
+          currentAreaNameChar++;
+
+          areaSizes[cell.obj] = 1;
+          perimeterLengths[cell.obj] = 0;
+        } else {
+          areaSizes[cell.obj] = areaSizes[cell.obj]! + 1;
+        }
+
+        // Perimeter length
+        for (CardinalDirection direction in CardinalDirection.values) {
+          if (!coordinates.canGoCDirection(direction)) {
+            perimeterLengths[cell.obj] = perimeterLengths[cell.obj]! + 1;
+          } else {
+            Coordinates neighbor = coordinates.goToCDirection(direction);
+            if (grid[neighbor].obj != cell.obj) {
+              perimeterLengths[cell.obj] = perimeterLengths[cell.obj]! + 1;
+            }
+          }
+        }
+      }
+    }
+    int price1 = areaSizes.keys.map((key) => areaSizes[key]! * perimeterLengths[key]!).sum;
+
+    return 'Part 1 price: $price1';
+  }
+
+}