style: enable HideUtilityClassConstructor in checkstyle (#5147)

src/main/java/com/thealgorithms/backtracking/ArrayCombination.java

@@ -7,7 +7,9 @@ import java.util.TreeSet;
  * Finds all permutations of 1...n of length k
  * @author TheClerici (<a href="https://github.com/TheClerici">git-TheClerici</a>)
  */
-public class ArrayCombination {
+public final class ArrayCombination {
+    private ArrayCombination() {
+    }
     private static int length;
 
     /**

src/main/java/com/thealgorithms/backtracking/Combination.java

@@ -9,7 +9,9 @@ import java.util.TreeSet;
  * Finds all permutations of given array
  * @author Alan Piao (<a href="https://github.com/cpiao3">git-Alan Piao</a>)
  */
-public class Combination {
+public final class Combination {
+    private Combination() {
+    }
 
     private static int length;
 

src/main/java/com/thealgorithms/backtracking/KnightsTour.java

@@ -26,7 +26,9 @@ import java.util.List;
         51  46  55  44  53   4  21  12
 
  */
-public class KnightsTour {
+public final class KnightsTour {
+    private KnightsTour() {
+    }
 
     private static final int BASE = 12;
     private static final int[][] MOVES = {

src/main/java/com/thealgorithms/backtracking/MColoring.java

@@ -14,7 +14,9 @@ class Node {
     Set<Integer> edges = new HashSet<Integer>();
 }
 
-public class MColoring {
+public final class MColoring {
+    private MColoring() {
+    }
     static int possiblePaint(ArrayList<Node> nodes, int n, int m) {
 
         // Create a visited array of n nodes

src/main/java/com/thealgorithms/backtracking/MazeRecursion.java

@@ -1,6 +1,8 @@
 package com.thealgorithms.backtracking;
 
-public class MazeRecursion {
+public final class MazeRecursion {
+    private MazeRecursion() {
+    }
 
     public static void mazeRecursion() {
         // First create a 2 dimensions array to mimic a maze map

src/main/java/com/thealgorithms/backtracking/NQueens.java

@@ -32,7 +32,9 @@ import java.util.List;
  * queen is not placed safely. If there is no such way then return an empty list
  * as solution
  */
-public class NQueens {
+public final class NQueens {
+    private NQueens() {
+    }
 
     public static void main(String[] args) {
         placeQueens(1);

src/main/java/com/thealgorithms/backtracking/Permutation.java

@@ -7,7 +7,9 @@ import java.util.List;
  * Finds all permutations of given array
  * @author Alan Piao (<a href="https://github.com/cpiao3">Git-Alan Piao</a>)
  */
-public class Permutation {
+public final class Permutation {
+    private Permutation() {
+    }
 
     /**
      * Find all permutations of given array using backtracking