Remove unnecessary code (#4141)

src/main/java/com/thealgorithms/datastructures/queues/CircularQueue.java

@@ -17,21 +17,13 @@ public class CircularQueue {
     }
 
     public boolean isEmpty() {
-        if (beginningOfQueue == -1) {
-            return true;
-        } else {
-            return false;
-        }
+        return beginningOfQueue == -1;
     }
 
     public boolean isFull() {
         if (topOfQueue + 1 == beginningOfQueue) {
             return true;
-        } else if (topOfQueue == size - 1 && beginningOfQueue == 0) {
-            return true;
-        } else {
-            return false;
-        }
+        } else return topOfQueue == size - 1 && beginningOfQueue == 0;
     }
 
     public void enQueue(int value) {

src/main/java/com/thealgorithms/datastructures/queues/Deques.java

@@ -91,13 +91,12 @@ public class Deques<T> {
         if (tail == null) {
             // If the deque is empty, add the node as the head and tail
             head = newNode;
-            tail = newNode;
         } else {
             // If the deque is not empty, insert the node as the new tail
             newNode.prev = tail;
             tail.next = newNode;
-            tail = newNode;
         }
+        tail = newNode;
 
         size++;
     }

src/main/java/com/thealgorithms/datastructures/queues/Queues.java

@@ -177,6 +177,6 @@ public class Queues {
 
         System.out.println(myQueue.peekFront()); // Will print 2
         System.out.println(myQueue.peekRear()); // Will print 7
-        System.out.println(myQueue.toString()); // Will print [2, 5, 3, 7]
+        System.out.println(myQueue); // Will print [2, 5, 3, 7]
     }
 }