Java ArrayDeque (Dengan Contoh)

Dalam tutorial ini, kita akan belajar tentang kelas ArrayDeque dan metodenya dengan bantuan contoh. Selain itu, kita akan belajar menggunakan deque array untuk mengimplementasikan tumpukan.

Di Java, kita dapat menggunakan ArrayDequekelas untuk mengimplementasikan antrian dan struktur data deque menggunakan array.

Antarmuka diimplementasikan oleh ArrayDeque

The ArrayDequekelas mengimplementasikan dua antarmuka ini:

• Antarmuka Antrian Java
• Antarmuka Deque Java

Membuat ArrayDeque

Untuk membuat deque array, kita harus mengimpor java.util.ArrayDequepaket.

Berikut adalah bagaimana kita dapat membuat deque array di Java:

 ArrayDeque animal = new ArrayDeque(); 

Di sini, Type menunjukkan jenis deque array. Sebagai contoh,

 // Creating String type ArrayDeque ArrayDeque animals = new ArrayDeque(); // Creating Integer type ArrayDeque ArrayDeque age = new ArrayDeque(); 

Metode ArrayDeque

The ArrayDequekelas menyediakan implementasi untuk semua metode hadir dalam Queuedan Dequeantarmuka.

Sisipkan Elemen ke Deque

1. Tambahkan elemen menggunakan add (), addFirst () dan addLast ()

• add() - menyisipkan elemen yang ditentukan di akhir deque array
• addFirst() - menyisipkan elemen yang ditentukan di awal deque array
• addLast()- menyisipkan yang ditentukan di akhir deret deque (setara dengan add())

Catatan: Jika deque array sudah penuh, semua metode ini add(), addFirst()dan addLast()lemparan IllegalStateException.

Sebagai contoh,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); // Using add() animals.add("Dog"); // Using addFirst() animals.addFirst("Cat"); // Using addLast() animals.addLast("Horse"); System.out.println("ArrayDeque: " + animals); ) ) 

Keluaran

 ArrayDeque: (Kucing, Anjing, Kuda) 

2. Sisipkan elemen menggunakan offer (), offerFirst (), dan offerLast ()

• offer() - menyisipkan elemen yang ditentukan di akhir deque array
• offerFirst() - menyisipkan elemen yang ditentukan di awal deque array
• offerLast() - menyisipkan elemen yang ditentukan di akhir deque array

Catatan: offer() , offerFirst()dan offerLast()kembali truejika unsur ini berhasil dimasukkan; jika deque array sudah penuh, metode ini akan kembali false.

Sebagai contoh,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); // Using offer() animals.offer("Dog"); // Using offerFirst() animals.offerFirst("Cat"); // Using offerLast() animals.offerLast("Horse"); System.out.println("ArrayDeque: " + animals); ) ) 

Keluaran

 ArrayDeque: (Kucing, Anjing, Kuda) 

Catatan: Jika deque array sudah penuh

• yang add()metode akan melempar pengecualian
• yang offer()kembali metodefalse

Akses ArrayDeque Elements

1. Mengakses elemen menggunakan getFirst () dan getLast ()

• getFirst() - mengembalikan elemen pertama dari deque array
• getLast() - mengembalikan elemen terakhir dari deque array

Catatan: Jika deque array kosong, getFirst()dan getLast()melempar NoSuchElementException.

Sebagai contoh,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Horse"); System.out.println("ArrayDeque: " + animals); // Get the first element String firstElement = animals.getFirst(); System.out.println("First Element: " + firstElement); // Get the last element String lastElement = animals.getLast(); System.out.println("Last Element: " + lastElement); ) ) 

Keluaran

 Larik Persamaan: (Anjing, Kucing, Kuda) Elemen Pertama: Anjing Elemen Terakhir: Kuda 

2. Akses elemen menggunakan metode peek (), peekFirst () dan peekLast ()

• peek() - mengembalikan elemen pertama dari deque array
• peekFirst()- mengembalikan elemen pertama dari array deque (setara dengan peek())
• peekLast() - mengembalikan elemen terakhir dari deque array

Sebagai contoh,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Horse"); System.out.println("ArrayDeque: " + animals); // Using peek() String element = animals.peek(); System.out.println("Head Element: " + element); // Using peekFirst() String firstElement = animals.peekFirst(); System.out.println("First Element: " + firstElement); // Using peekLast String lastElement = animals.peekLast(); System.out.println("Last Element: " + lastElement); ) ) 

Keluaran

 Jenis Huruf: (Anjing, Kucing, Kuda) Elemen Kepala: Anjing Elemen Pertama: Anjing Elemen Terakhir: Kuda 

Catatan: Jika deque array kosong peek(),, peekFirst()dan getLast()melempar NoSuchElementException.

Hapus Elemen ArrayDeque

1. Hapus elemen menggunakan metode remove (), removeFirst (), removeLast ()

• remove() - mengembalikan dan menghapus elemen dari elemen pertama dari array deque
• remove(element) - mengembalikan dan menghapus elemen yang ditentukan dari kepala deque array
• removeFirst()- mengembalikan dan menghapus elemen pertama dari array deque (setara dengan remove())
• removeLast() - mengembalikan dan menghapus elemen terakhir dari deque array

Note: If the array deque is empty, remove(), removeFirst() and removeLast() method throws an exception. Also, remove(element) throws an exception if the element is not found.

For example,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Cow"); animals.add("Horse"); System.out.println("ArrayDeque: " + animals); // Using remove() String element = animals.remove(); System.out.println("Removed Element: " + element); System.out.println("New ArrayDeque: " + animals); // Using removeFirst() String firstElement = animals.removeFirst(); System.out.println("Removed First Element: " + firstElement); // Using removeLast() String lastElement = animals.removeLast(); System.out.println("Removed Last Element: " + lastElement); ) ) 

Output

 ArrayDeque: (Dog, Cat, Cow, Horse) Removed Element: Dog New ArrayDeque: (Cat, Cow, Horse) Removed First Element: Cat Removed Last Element: Horse 

2. Remove elements using the poll(), pollFirst() and pollLast() method

• poll() - returns and removes the first element of the array deque
• pollFirst() - returns and removes the first element of the array deque (equivalent to poll())
• pollLast() - returns and removes the last element of the array deque

Note: If the array deque is empty, poll(), pollFirst() and pollLast() returns null if the element is not found.

For example,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Cow"); animals.add("Horse"); System.out.println("ArrayDeque: " + animals); // Using poll() String element = animals.poll(); System.out.println("Removed Element: " + element); System.out.println("New ArrayDeque: " + animals); // Using pollFirst() String firstElement = animals.pollFirst(); System.out.println("Removed First Element: " + firstElement); // Using pollLast() String lastElement = animals.pollLast(); System.out.println("Removed Last Element: " + lastElement); ) ) 

Output

 ArrayDeque: (Dog, Cat, Cow, Horse) Removed Element: Dog New ArrayDeque: (Cat, Cow, Horse) Removed First Element: Cat Removed Last Element: Horse 

3. Remove Element: using the clear() method

To remove all the elements from the array deque, we use the clear() method. For example,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Horse"); System.out.println("ArrayDeque: " + animals); // Using clear() animals.clear(); System.out.println("New ArrayDeque: " + animals); ) ) 

Output

 ArrayDeque: (Dog, Cat, Horse) New ArrayDeque: () 

Iterating the ArrayDeque

• iterator() - returns an iterator that can be used to iterate over the array deque
• descendingIterator() - returns an iterator that can be used to iterate over the array deque in reverse order

In order to use these methods, we must import the java.util.Iterator package. For example,

 import java.util.ArrayDeque; import java.util.Iterator; class Main ( public static void main(String() args) ( ArrayDeque animals= new ArrayDeque(); animals.add("Dog"); animals.add("Cat"); animals.add("Horse"); System.out.print("ArrayDeque: "); // Using iterator() Iterator iterate = animals.iterator(); while(iterate.hasNext()) ( System.out.print(iterate.next()); System.out.print(", "); ) System.out.print("ArrayDeque in reverse order: "); // Using descendingIterator() Iterator desIterate = animals.descendingIterator(); while(desIterate.hasNext()) ( System.out.print(desIterate.next()); System.out.print(", "); ) ) ) 

Output

 ArrayDeque: (Dog, Cat, Horse) ArrayDeque in reverse order: (Horse, Cat, Dog) 

Other Methods

Methods	Descriptions
element()	Returns an element from the head of the array deque.
contains(element)	Searches the array deque for the specified element. If the element is found, it returns true, if not it returns false.
size()	Returns the length of the array deque.
toArray()	Converts array deque to array and returns it.
clone()	Creates a copy of the array deque and returns it.

ArrayDeque as a Stack

To implement a LIFO (Last-In-First-Out) stacks in Java, it is recommended to use a deque over the Stack class. The ArrayDeque class is likely to be faster than the Stack class.

ArrayDeque provides the following methods that can be used for implementing a stack.

• push() - adds an element to the top of the stack
• peek() - returns an element from the top of the stack
• pop() - returns and removes an element from the top of the stack

For example,

 import java.util.ArrayDeque; class Main ( public static void main(String() args) ( ArrayDeque stack = new ArrayDeque(); // Add elements to stack stack.push("Dog"); stack.push("Cat"); stack.push("Horse"); System.out.println("Stack: " + stack); // Access element from top of stack String element = stack.peek(); System.out.println("Accessed Element: " + element); // Remove elements from top of stack String remElement = stack.pop(); System.out.println("Removed element: " + remElement); ) ) 

Output

 Stack: (Horse, Cat, Dog) Accessed Element: Horse Removed Element: Horse 

ArrayDeque Vs. LinkedList Class

Both ArrayDeque and Java LinkedList implements the Deque interface. However, there exist some differences between them.

• LinkedList supports null elements, whereas ArrayDeque doesn't.
• Setiap node dalam daftar tertaut menyertakan tautan ke node lain. Itu sebabnya LinkedListmembutuhkan penyimpanan lebih dari ArrayDeque.
• Jika Anda mengimplementasikan antrian atau struktur data deque, an ArrayDequecenderung lebih cepat daripada a LinkedList.