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  1. import java.util.*;
  2.  
  3. class Student {
  4. 	private String name;
  5. 	private int id;
  6.  
  7. 	public Student(int id, String name) {
  8. 		this.name = name;
  9. 		this.id = id;
  10. 	}
  11.  
  12. 	public void setId(int id) { this.id = id; }
  13. 	public String getName() { return name; }
  14. 	public int getId() { return id; }
  15. }
  16.  
  17. class StudentsList {
  18. 	private List<Student> students = new ArrayList<Student>();
  19.  
  20. 	private void updateIds() {
  21. 		int id = 0;
  22. 		for(Student t : students)
  23. 			t.setId(id++);
  24. 	}
  25.  
  26. 	public void add(String name) {
  27. 		students.add(new Student(students.size(),name));
  28. 	}
  29.  
  30. 	public void remove(int id) {
  31. 		students.remove(id);
  32. 		updateIds();
  33. 	}
  34.  
  35. 	public void insert(int id, String name) {
  36. 		students.add(id,new Student(id,name));
  37. 		updateIds();
  38. 	}
  39.  
  40. 	public Student get(int id) { return students.get(id); }
  41. 	public int size() { return students.size(); }
  42. }
  43.  
  44. class Professor {
  45. 	private StudentsList studentsList;
  46. 	private int nextId = 0;
  47.  
  48. 	public Professor(StudentsList studentsList) { this.studentsList = studentsList; }
  49.  
  50. 	public Student getNext() {
  51. 		if(nextId >= studentsList.size())
  52. 			nextId = 0;
  53. 		return studentsList.get(nextId++);
  54. 	}
  55.  
  56. 	public void studentHasBeenRemoved(int id) {
  57. 		if(id < nextId)
  58. 			--nextId;
  59. 	}
  60. }
  61.  
  62. class Remover {
  63. 	private StudentsList studentsList;
  64. 	private Professor professor;
  65.  
  66. 	public Remover(StudentsList studentsList, Professor professor) {
  67. 		this.studentsList = studentsList;
  68. 		this.professor = professor;
  69. 	}
  70.  
  71. 	public void remove(Student t) {
  72. 		professor.studentHasBeenRemoved(t.getId());
  73. 		studentsList.remove(t.getId());
  74. 	}
  75. }
  76.  
  77. public class Main {
  78. 	public static void main(String[] args) {
  79. 		StudentsList studentsList = new StudentsList();
  80. 		Professor professor = new Professor(studentsList);
  81. 		Remover remover = new Remover(studentsList, professor);
  82.  
  83. 		studentsList.add("aaaaa");
  84. 		studentsList.add("bbbbb");
  85. 		studentsList.add("ccccc");
  86. 		studentsList.add("ddddd");
  87. 		studentsList.add("eeeee");
  88. 		studentsList.add("fffff");
  89. 		studentsList.add("ggggg");
  90.  
  91. 		Student first = professor.getNext();
  92. 		System.out.println(first.getName());
  93. 		remover.remove(first);	//usuwam aaaaa
  94. 		remover.remove(studentsList.get(0)); //usuwam bbbbb
  95. 		remover.remove(studentsList.get(0)); //usuwam ccccc
  96.  
  97. 		int n = 7;
  98. 		while(n > 0) {
  99. 			System.out.println(professor.getNext().getName());
  100. 			--n;
  101. 		}
  102. 	}
  103. }
  104.  
  105.  
Success #stdin #stdout 0.08s 380160KB
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stdin
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Standard input is empty
stdout
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aaaaa
ddddd
eeeee
fffff
ggggg
ddddd
eeeee
fffff
https://ideone.com/G4R2wW
language:
Java (HotSpot 12)
created:
11 years ago
visibility:
public

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