Implement merge

src/aud/exam/prep/array/FullyUsedArrayProcessor.java

@@ -389,7 +389,30 @@ public class FullyUsedArrayProcessor<T> implements SequenceProcessor<T, FullyUse
 
     @Override
     public FullyUsedArray<T> merge(FullyUsedArray<T> a, FullyUsedArray<T> b, Comparator<T> cmp) {
-        throw new UnsupportedOperationException();
+        var newArray = new FullyUsedArray<T>();
+        newArray.theArray = Arrays.newArray(a.theArray.length + b.theArray.length);
+
+        var index = 0;
+        var indexA = 0;
+        var indexB = 0;
+
+        while (indexA < a.theArray.length && indexB < b.theArray.length) {
+            if (cmp.compare(a.theArray[indexA], b.theArray[indexB]) < 0) {
+                newArray.theArray[index++] = a.theArray[indexA++];
+            } else {
+                newArray.theArray[index++] = b.theArray[indexB++];
+            }
+        }
+
+        while (indexA < a.theArray.length) {
+            newArray.theArray[index++] = a.theArray[indexA++];
+        }
+
+        while (indexB < b.theArray.length) {
+            newArray.theArray[index++] = b.theArray[indexB++];
+        }
+
+        return newArray;
     }
 
     @Override

test/aud/exam/prep/SequenceProcessorTest.java

@@ -480,6 +480,25 @@ public abstract class SequenceProcessorTest<S> {
 
         S s = processor.alternate(a, b);
 
+        assertTrue(processor.check(s));
         assertIterableEquals(list, processor.iterate(s));
     }
+
+    @ParameterizedTest
+    @ArgumentsSource(DoubleListProvider.class)
+    void testThat_mergeWorks(List<Integer> listA, List<Integer> listB) {
+        listA.sort(cmp);
+        S a = processor.create(listA);
+
+        listB.sort(cmp);
+        S b = processor.create(listB);
+
+        listA.addAll(listB);
+        listA.sort(cmp);
+
+        S s = processor.merge(a, b, cmp);
+
+        assertTrue(processor.check(s));
+        assertIterableEquals(listA, processor.iterate(s));
+    }
 }