Fix

Author: Hardvan

src/main/java/com/thealgorithms/others/SkylineProblem.java

@@ -34,13 +34,27 @@ public class SkylineProblem {
     /**
      * Array of buildings to process. Must be initialized before use.
      */
-    public Building[] building;
+    private Building[] building;
 
     /**
      * Number of buildings added so far.
      */
     public int count;
 
+    /**
+     * Sets the building array to the specified size.
+     *
+     * @param size The size of the building array.
+     * @throws IllegalArgumentException if size is negative
+     */
+    public void setBuilding(int size) {
+        if (size < 0) {
+            throw new IllegalArgumentException("Size must be non-negative");
+        }
+        this.building = new Building[size];
+        this.count = 0;
+    }
+
     /**
      * Adds a building with the given left, height, and right values to the
      * buildings list.

src/test/java/com/thealgorithms/others/SkylineProblemTest.java

@@ -13,7 +13,7 @@ class SkylineProblemTest {
     @Test
     void testSingleBuildingSkyline() {
         SkylineProblem skylineProblem = new SkylineProblem();
-        skylineProblem.building = new SkylineProblem.Building[1];
+        skylineProblem.setBuilding(1);
         skylineProblem.add(2, 10, 9);
 
         List<SkylineProblem.Skyline> result = skylineProblem.findSkyline(0, 0);
@@ -24,7 +24,7 @@ void testSingleBuildingSkyline() {
     @Test
     void testTwoBuildingsSkyline() {
         SkylineProblem skylineProblem = new SkylineProblem();
-        skylineProblem.building = new SkylineProblem.Building[2];
+        skylineProblem.setBuilding(2);
         skylineProblem.add(1, 11, 5);
         skylineProblem.add(2, 6, 7);
 
@@ -48,7 +48,7 @@ void testMergeSkyline() {
     @Test
     void testMultipleBuildingsSkyline() {
         SkylineProblem skylineProblem = new SkylineProblem();
-        skylineProblem.building = new SkylineProblem.Building[3];
+        skylineProblem.setBuilding(3);
         skylineProblem.add(1, 10, 5);
         skylineProblem.add(2, 15, 7);
         skylineProblem.add(3, 12, 9);
@@ -65,15 +65,15 @@ void testAddBuildingInvalidCases() {
         Exception ex = assertThrows(IllegalStateException.class, () -> skylineProblem.add(1, 2, 3));
         assertTrue(ex.getMessage().contains("not initialized"));
 
-        skylineProblem.building = new SkylineProblem.Building[1];
+        skylineProblem.setBuilding(1);
         skylineProblem.add(1, 2, 3);
         // Array full
         Exception ex2 = assertThrows(IllegalStateException.class, () -> skylineProblem.add(4, 5, 6));
         assertTrue(ex2.getMessage().contains("full"));
 
         // Invalid left >= right
         SkylineProblem skylineProblem2 = new SkylineProblem();
-        skylineProblem2.building = new SkylineProblem.Building[1];
+        skylineProblem2.setBuilding(1);
         Exception ex3 = assertThrows(IllegalArgumentException.class, () -> skylineProblem2.add(5, 2, 2));
         assertTrue(ex3.getMessage().contains("Left coordinate"));
 
@@ -89,7 +89,7 @@ void testFindSkylineInvalidCases() {
         Exception ex = assertThrows(IllegalArgumentException.class, () -> skylineProblem.findSkyline(0, 0));
         assertTrue(ex.getMessage().contains("not initialized"));
 
-        skylineProblem.building = new SkylineProblem.Building[2];
+        skylineProblem.setBuilding(2);
         skylineProblem.count = 1;
         Exception ex2 = assertThrows(IllegalArgumentException.class, () -> skylineProblem.findSkyline(0, 1));
         assertTrue(ex2.getMessage().contains("Invalid start or end index"));
@@ -98,18 +98,8 @@ void testFindSkylineInvalidCases() {
     @Test
     void testMergeSkylineNullCases() {
         SkylineProblem skylineProblem = new SkylineProblem();
-        Exception ex1 = assertThrows(NullPointerException.class, new org.junit.jupiter.api.function.Executable() {
-            @Override
-            public void execute() {
-                skylineProblem.mergeSkyline(null, List.of());
-            }
-        });
-        Exception ex2 = assertThrows(NullPointerException.class, new org.junit.jupiter.api.function.Executable() {
-            @Override
-            public void execute() {
-                skylineProblem.mergeSkyline(List.of(), null);
-            }
-        });
+        Exception ex1 = assertThrows(NullPointerException.class, () -> skylineProblem.mergeSkyline(null, List.of()));
+        Exception ex2 = assertThrows(NullPointerException.class, () -> skylineProblem.mergeSkyline(List.of(), null));
         assertTrue(ex1.getMessage().contains("sky1"));
         assertTrue(ex2.getMessage().contains("sky2"));
     }