ds-homework/Queue.java at main · ebimoein13/ds-homework · GitHub

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public class Queue {

    int[] arr;
    int front;
    int rear;
    int size;
    int capacity;

    public Queue(int cap) {
        capacity = cap;
        arr = new int[capacity];
        front = 0;
        rear = -1;
        size = 0;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public boolean isFull() {
        return size == capacity;
    }

    public void enqueue(int x) {
        if (isFull())
            return;

        rear++;
        arr[rear] = x;
        size++;
    }

    public int dequeue() {
        if (isEmpty())
            return -1;

        int val = arr[front];
        front++;
        size--;
        return val;
    }

    public int peek() {
        if (isEmpty())
            return -1;

        return arr[front];
    }

    public void printQueue() {
        for (int i = front; i <= rear; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

}