import java.util.LinkedList;

import java.util.Queue;

import java.util.ArrayList;

import java.util.List;

class QueueFlattener {

/**

* Flattens a nested structure of queues into a single list for monitoring.

*

* @param queues A list of queues to flatten.

* @return A list containing all elements from the input queues.

*/

public static <T> List<T> flattenQueues(List<Queue<T>> queues) {

List<T> flattenedList = new ArrayList<>(); // Initialize an empty list to store flattened elements.

if (queues == null || queues.isEmpty()) {

return flattenedList; // Return empty list if input is null or empty.

}

for (Queue<T> queue : queues) { // Iterate through each queue in the input list.

if (queue != null) { // Check if the queue is not null

while (!queue.isEmpty()) { // Iterate while the queue is not empty.

flattenedList.add(queue.poll()); // Dequeue an element and add it to the flattened list.

}

}

}

return flattenedList; // Return the flattened list.

}

public static void main(String[] args) {

// Example usage:

Queue<Integer> queue1 = new LinkedList<>();

queue1.add(1);

queue1.add(2);

queue1.add(3);

Queue<Integer> queue2 = new LinkedList<>();

queue2.add(4);

queue2.add(5);

Queue<Integer> queue3 = new LinkedList<>();

queue3.add(6);

List<Queue<Integer>> queues = new ArrayList<>();

queues.add(queue1);

queues.add(queue2);

queues.add(queue3);

List<Integer> flattened = flattenQueues(queues);

System.out.println(flattened); // Output: [1, 2, 3, 4, 5, 6]

}

}