style: enable AvoidNestedBlocks in checkstyle

checkstyle.xml

@@ -152,7 +152,7 @@
 
     <!-- Checks for blocks. You know, those {}'s         -->
     <!-- See https://checkstyle.org/checks/blocks/index.html -->
-    <!-- TODO <module name="AvoidNestedBlocks"/> -->
+    <module name="AvoidNestedBlocks"/>
     <!-- TODO <module name="EmptyBlock"/> -->
     <!-- TODO <module name="LeftCurly"/> -->
     <module name="NeedBraces"/>

src/main/java/com/thealgorithms/datastructures/hashmap/hashing/Main.java

@@ -23,31 +23,30 @@ public static void main(String[] args) {
             choice = scan.nextInt();
 
             switch (choice) {
-            case 1: {
+            case 1:
                 System.out.println("Enter the Key: ");
                 key = scan.nextInt();
                 h.insertHash(key);
                 break;
-            }
-            case 2: {
+
+            case 2:
                 System.out.println("Enter the Key delete:  ");
                 key = scan.nextInt();
                 h.deleteHash(key);
                 break;
-            }
-            case 3: {
+
+            case 3:
                 System.out.println("Print table");
                 h.displayHashtable();
                 break;
-            }
-            case 4: {
+
+            case 4:
                 scan.close();
                 return;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + choice);
             }
-            }
         }
     }
 }

src/main/java/com/thealgorithms/datastructures/hashmap/hashing/MainCuckooHashing.java

@@ -27,45 +27,44 @@ public static void main(String[] args) {
             choice = scan.nextInt();
 
             switch (choice) {
-            case 1: {
+            case 1:
                 System.out.println("Enter the Key: ");
                 key = scan.nextInt();
                 h.insertKey2HashTable(key);
                 break;
-            }
-            case 2: {
+
+            case 2:
                 System.out.println("Enter the Key delete:  ");
                 key = scan.nextInt();
                 h.deleteKeyFromHashTable(key);
                 break;
-            }
-            case 3: {
+
+            case 3:
                 System.out.println("Print table:\n");
                 h.displayHashtable();
                 break;
-            }
-            case 4: {
+
+            case 4:
                 scan.close();
                 return;
-            }
-            case 5: {
+
+            case 5:
                 System.out.println("Enter the Key to find and print:  ");
                 key = scan.nextInt();
                 System.out.println("Key: " + key + " is at index: " + h.findKeyInTable(key) + "\n");
                 break;
-            }
-            case 6: {
+
+            case 6:
                 System.out.printf("Load factor is: %.2f%n", h.checkLoadFactor());
                 break;
-            }
-            case 7: {
+
+            case 7:
                 h.reHashTableIncreasesTableSize();
                 break;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + choice);
             }
-            }
         }
     }
 }

src/main/java/com/thealgorithms/maths/MatrixUtil.java

@@ -1,8 +1,6 @@
 package com.thealgorithms.maths;
 
 import java.math.BigDecimal;
-import java.util.Arrays;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.stream.IntStream;
@@ -15,19 +13,19 @@ public final class MatrixUtil {
     private MatrixUtil() {
     }
 
-    public static boolean isValid(final BigDecimal[][] matrix) {
+    private static boolean isValid(final BigDecimal[][] matrix) {
         return matrix != null && matrix.length > 0 && matrix[0].length > 0;
     }
 
-    public static boolean hasEqualSizes(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
+    private static boolean hasEqualSizes(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
         return (isValid(matrix1) && isValid(matrix2) && matrix1.length == matrix2.length && matrix1[0].length == matrix2[0].length);
     }
 
-    public static boolean canMultiply(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
+    private static boolean canMultiply(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2) {
         return (isValid(matrix1) && isValid(matrix2) && matrix1[0].length == matrix2.length);
     }
 
-    public static Optional<BigDecimal[][]> operate(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2, final BiFunction<BigDecimal, BigDecimal, BigDecimal> operation) {
+    private static Optional<BigDecimal[][]> operate(final BigDecimal[][] matrix1, final BigDecimal[][] matrix2, final BiFunction<BigDecimal, BigDecimal, BigDecimal> operation) {
         if (!hasEqualSizes(matrix1, matrix2)) {
             return Optional.empty();
         }
@@ -82,78 +80,4 @@ public static Optional<BigDecimal[][]> multiply(final BigDecimal[][] matrix1, fi
 
         return Optional.of(result);
     }
-
-    public static void assertThat(final BigDecimal[][] actual, final BigDecimal[][] expected) {
-        if (!Objects.deepEquals(actual, expected)) {
-            throw new AssertionError(String.format("expected=%s but was actual=%s", Arrays.deepToString(expected), Arrays.deepToString(actual)));
-        }
-    }
-
-    public static void main(final String[] args) {
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(3), new BigDecimal(2)},
-                {new BigDecimal(0), new BigDecimal(1)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(1), new BigDecimal(3)},
-                {new BigDecimal(2), new BigDecimal(0)},
-            };
-
-            final BigDecimal[][] actual = add(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(4), new BigDecimal(5)},
-                {new BigDecimal(2), new BigDecimal(1)},
-            };
-
-            assertThat(actual, expected);
-        }
-
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(1), new BigDecimal(4)},
-                {new BigDecimal(5), new BigDecimal(6)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(2), new BigDecimal(0)},
-                {new BigDecimal(-2), new BigDecimal(-3)},
-            };
-
-            final BigDecimal[][] actual = subtract(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(-1), new BigDecimal(4)},
-                {new BigDecimal(7), new BigDecimal(9)},
-            };
-
-            assertThat(actual, expected);
-        }
-
-        {
-            final BigDecimal[][] matrix1 = {
-                {new BigDecimal(1), new BigDecimal(2), new BigDecimal(3)},
-                {new BigDecimal(4), new BigDecimal(5), new BigDecimal(6)},
-                {new BigDecimal(7), new BigDecimal(8), new BigDecimal(9)},
-            };
-
-            final BigDecimal[][] matrix2 = {
-                {new BigDecimal(1), new BigDecimal(2)},
-                {new BigDecimal(3), new BigDecimal(4)},
-                {new BigDecimal(5), new BigDecimal(6)},
-            };
-
-            final BigDecimal[][] actual = multiply(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
-
-            final BigDecimal[][] expected = {
-                {new BigDecimal(22), new BigDecimal(28)},
-                {new BigDecimal(49), new BigDecimal(64)},
-                {new BigDecimal(76), new BigDecimal(100)},
-            };
-
-            assertThat(actual, expected);
-        }
-    }
 }

src/main/java/com/thealgorithms/misc/Sort012D.java

@@ -33,28 +33,27 @@ public static void sort012(int[] a) {
         int temp;
         while (mid <= h) {
             switch (a[mid]) {
-            case 0: {
+            case 0:
                 temp = a[l];
                 a[l] = a[mid];
                 a[mid] = temp;
                 l++;
                 mid++;
                 break;
-            }
+
             case 1:
                 mid++;
                 break;
-            case 2: {
+            case 2:
                 temp = a[mid];
                 a[mid] = a[h];
                 a[h] = temp;
                 h--;
                 break;
-            }
-            default: {
+
+            default:
                 throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }
-            }
         }
         System.out.println("the Sorted array is ");
         for (int i = 0; i < a.length; i++) {

src/main/java/com/thealgorithms/sorts/DNFSort.java

@@ -13,24 +13,24 @@ static void sort012(int[] a, int arrSize) {
         int temp;
         while (mid <= high) {
             switch (a[mid]) {
-            case 0: {
+            case 0:
                 temp = a[low];
                 a[low] = a[mid];
                 a[mid] = temp;
                 low++;
                 mid++;
                 break;
-            }
+
             case 1:
                 mid++;
                 break;
-            case 2: {
+            case 2:
                 temp = a[mid];
                 a[mid] = a[high];
                 a[high] = temp;
                 high--;
                 break;
-            }
+
             default:
                 throw new IllegalArgumentException("Unexpected value: " + a[mid]);
             }

src/test/java/com/thealgorithms/maths/MatrixUtilTest.java

@@ -0,0 +1,79 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+import org.junit.jupiter.api.Test;
+
+class MatrixUtilTest {
+
+    @Test
+    void add() {
+        final BigDecimal[][] matrix1 = {
+            {new BigDecimal(3), new BigDecimal(2)},
+            {BigDecimal.ZERO, BigDecimal.ONE},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {BigDecimal.ONE, new BigDecimal(3)},
+            {new BigDecimal(2), BigDecimal.ZERO},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.add(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(4), new BigDecimal(5)},
+            {new BigDecimal(2), BigDecimal.ONE},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+    @Test
+    void subtract() {
+        final BigDecimal[][] matrix1 = {
+            {BigDecimal.ONE, new BigDecimal(4)},
+            {new BigDecimal(5), new BigDecimal(6)},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {new BigDecimal(2), BigDecimal.ZERO},
+            {new BigDecimal(-2), new BigDecimal(-3)},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.subtract(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(-1), new BigDecimal(4)},
+            {new BigDecimal(7), new BigDecimal(9)},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+
+    @Test
+    void multiply() {
+
+        final BigDecimal[][] matrix1 = {
+            {BigDecimal.ONE, new BigDecimal(2), new BigDecimal(3)},
+            {new BigDecimal(4), new BigDecimal(5), new BigDecimal(6)},
+            {new BigDecimal(7), new BigDecimal(8), new BigDecimal(9)},
+        };
+
+        final BigDecimal[][] matrix2 = {
+            {BigDecimal.ONE, new BigDecimal(2)},
+            {new BigDecimal(3), new BigDecimal(4)},
+            {new BigDecimal(5), new BigDecimal(6)},
+        };
+
+        final BigDecimal[][] actual = MatrixUtil.multiply(matrix1, matrix2).orElseThrow(() -> new AssertionError("Could not compute matrix!"));
+
+        final BigDecimal[][] expected = {
+            {new BigDecimal(22), new BigDecimal(28)},
+            {new BigDecimal(49), new BigDecimal(64)},
+            {new BigDecimal(76), new BigDecimal(100)},
+        };
+
+        assertTrue(Objects.deepEquals(actual, expected));
+    }
+}