Link list part 2

Link list part 2

• 1.
  Linked Lists
• 2.
  Linked Stacks andQueues front rear top 0 0 Linked Stack Linked Queue
• 3.
  Template of Queues classQueue; class Node { friend class Queue; private: int info; Node *link; }; class Queue { public: Queue() {front = rear = NULL;}; void Add(int); int Delete(); bool Empty(); private: Node *front, *rear; };
• 4.
  Queue Operations front ×rear Queue::Queue() { first =rear = NULL; };
• 5.
  bool Empty() { if (front==NULL) return TRUE; else return FALSE; } Queue Operations
• 6.
  int Queue::Delete() { if (Empty()) { cout<<“Queue underflow”; exit(1); } Node *temp = front; int x = temp->info; front = temp->link; if (front== NULL) rear = NULL; delete temp; return x; } Queue Operations front rear ×× temp 642 8
• 7.
  void Queue::Add(int x) { Node*temp = new Node; temp->info=x; temp->link = NULL; if (rear== NULL) front = temp; else rear->link = temp; rear = temp; } Queue Operations front rear × temp 642 8 ×10×
• 8.
  Various Linked Lists Adding an element in the beginning of the list, or the end of the list  Chains, circular lists  Singly linked lists, doubly linked lists  Etc.
• 9.
  Circular List  CircularList: The tail of the list points back to the head  There is no NULL pointer to “end” the list. 62 84
• 10.
  Circular List  Thereis no first and last node in circular list so we establish a first, last node by convention First Node Last Node Last  An external pointer is used to point to last node. 62 84
• 11.
  Stacks as aCircular List Let last be the pointer pointing to the last node in the stack and first node be considered as top of the stack. Implementation of Stack class Stack; class Node { friend class Stack; private: int info; Node *link; }; class Stack { public: Stack() {last = NULL;}; void Push(int); int Pop(); bool Empty(); private: Node *last; };
• 12.
  bool Stack::Empty() { if (last== NULL) return TRUE; else return FALSE: } Stack Operations
• 13.
  void Stack::Push(int x) { Node* temp = new Node; temp->info = x; if (last == NULL) last = temp; else temp->link = last->link; last->link = temp; } PUSH 642 last 1 temp
• 14.
  int Stackint::Pop() { int x;Node *temp; if (Empty()) {cout << “Empty Stack”; exit(1);} temp = last->link; x = temp->info; if (temp == last) last = NULL; else last->link = temp->link; delete temp; return x; } POP 642 last 1 temp
• 15.
  void Queue::Add(int x) { intx; Node *temp= new Node; temp->info = x; if (Empty()) last = temp; else temp->link = last->link; last->link = temp; last = temp; } Queue As Circular List 642 last 1 temp 8
• 16.
  void Queue::DelAfter(Node *p) { intx; Node *temp; if (p==NULL || p==p->link) { cout << “void deletion”; return; } temp = p->link; x = p->info; p->link = temp->link; delete temp; } DELAFTER() 642 last 1 temp 8 p
• 17.
  read n; read(name); while (name!= END) { insert name on the circular list; read(name); } while (there is more than one node on the list) { count through n-1 nodes on the list; print the name in the nth node; delete nth node } Print the name of the only node on the list Josephus Problem
• 18.
   List cannot be traversed backward.  A node can not be deleted from it, given only a pointer to that node. Solution is to use a Doubly Linked List Shortcomings of circular list
• 19.
  Doubly-Linked Lists  Eachnode contains two pointers, one to its successor and one to its predecessor.  Doubly linked list can be linear or circular. 88NULL 42 109 NULL head left info right 88 42 109
• 20.
  Same basic functionsoperate on list  Insertleft()  Insertright()  Delete()  deleteleft()  deleteright() We have left(right(p)) =p = right(left(p)) Doubly-Linked Lists
• 21.
  Doubly Link List Letfirst be the pointer pointing to the first node in the Doubly. Implementation of Doubly class Doubly; class Node { friend class Doubly; private: int info; Node *left, *right; }; class Doubly { public: Doubly() {first = NULL;}; ----------- private: Node *first; };
• 22.
  Delete int Doubly::Delete(Node *p) { Node*q, *r; int x; if (p==NULL) { cout << “void deletion”; return;} x = p->info; q = p->left; r = p->right; q->right = r; r->left = q; delete p;
• 23.
  DeleteLeft void Doubly:: DelRight(Node*p) { Node *q, *temp; int x; r = p->right; temp = r->right; p->right = temp; if (temp!=NULL) temp->left = p; cout << r->info; delete r; }
• 24.
  Insertright void Doubly:: insertright(Node*p, int x) { Node *q, *r; if (p==NULL) { cout << “void insertion”; return;} q = new Node; q->info = x; r = p->right; r->left = q; q->right = r; q->left = p; p->right = q;
• 25.
  Insert on headside void Doubly:: Insert(int x) { Node *q, *r; r = first; q = new Node; q->info = x; q->right = r; q->left = NULL; r->left = q; first = q; }
• 26.
  Deletion on headside void Doubly:: Delete(int v) { Node *q, *r; int x; r = first; q= r->right; q->left = NULL; r->right = NULL; x = r->info; first = q; delete r; }