1. import java.util.LinkedList;
  2. import java.util.Queue;
  3. import java.util.ArrayList;
  4. import java.util.List;
  6. public class QueueMerger {
  8. /**
  9. * Merges multiple queues into a single queue, performing basic input validation.
  10. *
  11. * @param queues A list of queues to merge.
  12. * @return A new queue containing all elements from the input queues, or null if
  13. * input is invalid.
  14. */
  15. public static <T> Queue<T> mergeQueues(List<Queue<T>> queues) {
  17. if (queues == null) {
  18. return null; // Handle null input
  19. }
  21. if (queues.isEmpty()) {
  22. return new LinkedList<>(); // Return empty queue if input list is empty
  23. }
  25. Queue<T> mergedQueue = new LinkedList<>();
  27. for (Queue<T> queue : queues) {
  28. if (queue == null) {
  29. continue; // Skip null queues
  30. }
  32. // Add elements from each queue to the merged queue
  33. while (!queue.isEmpty()) {
  34. mergedQueue.offer(queue.poll());
  35. }
  36. }
  38. return mergedQueue;
  39. }
  41. public static void main(String[] args) {
  42. //Example Usage
  43. Queue<Integer> q1 = new LinkedList<>();
  44. q1.offer(1);
  45. q1.offer(2);
  47. Queue<Integer> q2 = new LinkedList<>();
  48. q2.offer(3);
  49. q2.offer(4);
  51. Queue<Integer> q3 = new LinkedList<>();
  52. q3.offer(5);
  54. List<Queue<Integer>> queues = new ArrayList<>();
  55. queues.add(q1);
  56. queues.add(q2);
  57. queues.add(q3);
  59. Queue<Integer> merged = mergeQueues(queues);
  61. if (merged != null) {
  62. System.out.println("Merged Queue: " + merged);
  63. }
  64. }
  65. }

Add your comment