add null checker in algorithm

Author: bri-harris

src/main/java/com/thealgorithms/randomized/ClosestPair.java

@@ -76,6 +76,13 @@ public static Object[] rabinRandomizedClosestPair(List<Point> points) {
             }
         }
 
+        // Confirm neither closestA nor closestB are null
+        if (closestA == null || closestB == null) {
+            closestA = points.get(0);
+            closestB = points.get(1);
+            delta = euclideanDistance(closestA, closestB);
+        }
+
         // Create a grid, We will use "Probabilistic Filtering" by only checking
         //  neighboring grids to prevent bruteforce checking outside initialization
         Map<String, Point> grid = new HashMap<>();

src/test/java/com/thealgorithms/randomized/ClosestPairTest.java

@@ -23,11 +23,8 @@ void testStandardCaseClosestPair() {
     void testTwoDistinctPoints() {
         List<Point> points = Arrays.asList(new Point(1, 2), new Point(2, 3));
         Object[] closestPair = ClosestPair.rabinRandomizedClosestPair(points);
-
-        // Add null check for closestPair
-        assertNotNull(closestPair, "Closest pair result should not be null");
-        assertTrue((closestPair[0].equals(points.get(0)) && closestPair[1].equals(points.get(1))) || (closestPair[1].equals(points.get(0)) && closestPair[0].equals(points.get(1))), "The closest pair should include the given distinct points");
-        assertEquals(closestPair[2], ClosestPair.euclideanDistance(points.get(0), points.get(1)), "The calculated distance should match the Euclidean distance");
+        assertTrue((closestPair[0].equals(points.get(0)) && closestPair[1].equals(points.get(1))) || (closestPair[1].equals(points.get(0)) && closestPair[0].equals(points.get(1))));
+        assertEquals(closestPair[2], ClosestPair.euclideanDistance(points.get(0), points.get(1)));
     }
 
     @Test