feat: solve day 12 part 1

src/main/java/com/adventofcode/flashk/common/Array2DUtil.java

@@ -21,6 +21,19 @@ public static char[][] transpose(char[][] array) {
         return transposedArray;
     }
 
+    /*
+    public static <T> T[][] transpose(T[][] array) {
+        int rows = array.length;
+        int cols = array[0].length;
+        char[][] transposedArray = new char[cols][rows];
+        for(int row = 0; row < rows; row++) {
+            for(int col = 0; col < cols; col++) {
+                transposedArray[col][row] = array[row][col];
+            }
+        }
+        return transposedArray;
+    }*/
+
     /**
      * Paints the given array.
      * @param map the array to paint

src/main/java/com/adventofcode/flashk/day12/GardenGroups.java

@@ -0,0 +1,168 @@
+package com.adventofcode.flashk.day12;
+
+import com.adventofcode.flashk.common.Vector2;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class GardenGroups {
+
+    private int rows;
+    private int cols;
+    private GardenPlot[][] map;
+    private final Map<Integer, Integer> regionAreas = new HashMap<>();
+
+    public GardenGroups(char[][] inputs) {
+
+        rows = inputs.length;
+        cols = inputs[0].length;
+        map = new GardenPlot[rows][cols];
+
+        for(int row = 0; row < rows; row++){
+            for(int col = 0; col < cols; col++) {
+                map[row][col] = new GardenPlot(inputs[row][col], new Vector2(col, row));
+            }
+        }
+
+    }
+
+    public long solveA() {
+        findRegions();
+        return calculatePrice();
+    }
+
+    public long solveB() {
+        findRegions();
+        // TODO calculate sides of each region
+        // then calculate price
+        return 0L;
+    }
+
+    private void findRegions() {
+        int regionId = 1;
+        for(int row = 0; row < rows; row++) {
+            for(int col = 0; col < cols; col++) {
+                if(!map[row][col].hasRegion()) {
+                    int regionArea = findRegion(map[row][col], map[row][col].getPlant(), regionId);
+                    regionAreas.put(regionId, regionArea);
+                    regionId++;
+                }
+
+            }
+        }
+    }
+
+    private int findRegion(GardenPlot gardenPlot, char plant, int regionId) {
+
+        if(gardenPlot.isVisited()) {
+            return 0;
+        }
+
+        if(gardenPlot.hasRegion()) {
+            return 0;
+        }
+
+        if(gardenPlot.getPlant() != plant) {
+            return 0;
+        }
+
+        int area = 1;
+        gardenPlot.setVisited(true);
+        gardenPlot.setRegionId(regionId);
+
+        Set<GardenPlot> adjacentPlots = getAdjacentPlots(gardenPlot);
+
+        for(GardenPlot adjacentPlot : adjacentPlots) {
+            area += findRegion(adjacentPlot, plant, regionId);
+        }
+
+        gardenPlot.setVisited(false);
+
+        return area;
+    }
+
+    private long calculatePrice() {
+
+        long price = 0;
+
+        for(int row = 0; row < rows; row++) {
+
+            GardenPlot previousPlot = null;
+            for(int col = 0; col < cols;col++) {
+                GardenPlot plot = map[row][col];
+
+                if(previousPlot == null) {
+                    price += regionAreas.get(plot.getRegionId());
+                } else if(previousPlot.getRegionId() != plot.getRegionId()) {
+                    price += regionAreas.get(previousPlot.getRegionId());
+                    price += regionAreas.get(plot.getRegionId());
+                }
+
+                previousPlot = plot;
+            }
+
+            // Add price of right-most fence
+            price += regionAreas.get(previousPlot.getRegionId());
+
+        }
+
+
+        for(int col = 0; col < cols; col++) {
+
+            GardenPlot previousPlot = null;
+            for(int row = 0; row < rows; row++) {
+                GardenPlot plot = map[row][col];
+
+                if(previousPlot == null) {
+                    price += regionAreas.get(plot.getRegionId());
+                } else if(previousPlot.getRegionId() != plot.getRegionId()) {
+                    price += regionAreas.get(previousPlot.getRegionId());
+                    price += regionAreas.get(plot.getRegionId());
+                }
+
+                previousPlot = plot;
+            }
+
+            // Add price of right-most fence
+            price += regionAreas.get(previousPlot.getRegionId());
+        }
+
+        return price;
+
+    }
+
+    private Set<GardenPlot> getAdjacentPlots(GardenPlot gardenPlot) {
+
+        Set<GardenPlot> adjacentPlots = new HashSet<>();
+
+        Vector2 initialPos = gardenPlot.getPosition();
+
+        Vector2 nextPos = Vector2.transform(initialPos, Vector2.left());
+        if(isInbounds(nextPos)) {
+            adjacentPlots.add(map[nextPos.getY()][nextPos.getX()]);
+        }
+
+        nextPos = Vector2.transform(initialPos, Vector2.right());
+        if(isInbounds(nextPos)) {
+            adjacentPlots.add(map[nextPos.getY()][nextPos.getX()]);
+        }
+
+        nextPos = Vector2.transform(initialPos, Vector2.up());
+        if(isInbounds(nextPos)) {
+            adjacentPlots.add(map[nextPos.getY()][nextPos.getX()]);
+        }
+
+        nextPos = Vector2.transform(initialPos, Vector2.down());
+        if(isInbounds(nextPos)) {
+            adjacentPlots.add(map[nextPos.getY()][nextPos.getX()]);
+        }
+
+        return adjacentPlots;
+    }
+
+    private boolean isInbounds(Vector2 pos) {
+        return (pos.getY() >= 0 && pos.getY() < rows && pos.getX() >= 0 && pos.getX() < cols);
+    }
+}

src/main/java/com/adventofcode/flashk/day12/GardenPlot.java

@@ -0,0 +1,27 @@
+package com.adventofcode.flashk.day12;
+
+import com.adventofcode.flashk.common.Vector2;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+public class GardenPlot {
+
+    private char plant;
+
+    @Setter
+    private int regionId = 0;
+    private Vector2 position;
+
+    @Setter
+    private boolean visited = false;
+
+    public GardenPlot(char plant, Vector2 position) {
+        this.plant = plant;
+        this.position = position;
+    }
+
+    public boolean hasRegion() {
+        return regionId != 0;
+    }
+}

src/test/java/com/adventofcode/flashk/day12/Day12Test.java

@@ -34,9 +34,10 @@ public class Day12Test extends PuzzleTest {
 	public void testSolvePart1Sample() {
 
 		// Read input file
-		List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
+		char[][] inputs = Input.read2DCharArray(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
 
-		assertEquals(0L,0L);
+		GardenGroups gardenGroups = new GardenGroups(inputs);
+		assertEquals(1930L, gardenGroups.solveA());
 	}
 
 	@Test
@@ -47,10 +48,10 @@ public void testSolvePart1Sample() {
 	public void testSolvePart1Input() {
 
 		// Read input file
-		List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE);
-
-		System.out.println("Solution: ");
-		assertEquals(0L,0L);
+		char[][] inputs = Input.read2DCharArray(INPUT_FOLDER, TestFilename.INPUT_FILE);
+		GardenGroups gardenGroups = new GardenGroups(inputs);
+		System.out.println("Solution: "+gardenGroups.solveA());
+		assertEquals(1424472L,gardenGroups.solveA());
 
 	}
 
@@ -62,9 +63,9 @@ public void testSolvePart1Input() {
 	public void testSolvePart2Sample() {
 
 		// Read input file
-		List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
-
-		assertEquals(0L,0L);
+		char[][] inputs = Input.read2DCharArray(INPUT_FOLDER, TestFilename.INPUT_FILE_SAMPLE);
+		GardenGroups gardenGroups = new GardenGroups(inputs);
+		assertEquals(1206L,0L);
 	}
 
 	@Test
@@ -75,8 +76,8 @@ public void testSolvePart2Sample() {
 	public void testSolvePart2Input() {
 
 		// Read input file
-		List<String> inputs = Input.readStringLines(INPUT_FOLDER, TestFilename.INPUT_FILE);
-
+		char[][] inputs = Input.read2DCharArray(INPUT_FOLDER, TestFilename.INPUT_FILE);
+		GardenGroups gardenGroups = new GardenGroups(inputs);
 		System.out.println("Solution: ");
 		assertEquals(0L,0L);