90 lines
2.0 KiB
Java
90 lines
2.0 KiB
Java
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import java.util.NoSuchElementException;
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public class SimpleQueue<T> {
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private static class Node<T> {
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T value;
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Node<T> next;
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Node(T value) {
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this.value = value;
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}
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}
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private Node<T> head; // Le début de la file
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private Node<T> tail; // La fin de la file
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private int size;
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public SimpleQueue() {
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head = null;
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tail = null;
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size = 0;
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}
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/**
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* Ajoute un élément à la fin de la file.
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*
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* @param element L'élément à ajouter.
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*/
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public void enqueue(T element) {
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Node<T> newNode = new Node<>(element);
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if (isEmpty()) {
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head = tail = newNode;
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} else {
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tail.next = newNode;
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tail = newNode;
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}
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size++;
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}
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/**
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* Retire et renvoie l'élément en tête de la file.
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*
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* @return L'élément retiré.
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* @throws NoSuchElementException si la file est vide.
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*/
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public T dequeue() {
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if (isEmpty()) {
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throw new NoSuchElementException("Queue is empty");
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}
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T value = head.value;
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head = head.next;
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if (head == null) { // Si la file est désormais vide
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tail = null;
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}
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size--;
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return value;
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}
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/**
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* Renvoie l'élément en tête de la file sans le retirer.
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*
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* @return L'élément en tête.
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* @throws NoSuchElementException si la file est vide.
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*/
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public T peek() {
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if (isEmpty()) {
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throw new NoSuchElementException("Queue is empty");
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}
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return head.value;
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}
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/**
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* Vérifie si la file est vide.
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*
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* @return true si la file est vide, false sinon.
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*/
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public boolean isEmpty() {
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return size == 0;
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}
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/**
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* Renvoie le nombre d'éléments dans la file.
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*
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* @return La taille de la file.
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*/
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public int size() {
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return size;
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}
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}
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