java 栈，队列，链表，双链表，树

// stack.java
// demonstrates stacks
// to run this program: C>java StackApp
////////////////////////////////////////////////////////////////
class StackX
   {
   private int maxSize;        // size of stack array
   private long[] stackArray;
   private int top;            // top of stack
//--------------------------------------------------------------
   public StackX(int s)         // constructor
      {
      maxSize = s;             // set array size
      stackArray = new long[maxSize];  // create array
      top = -1;                // no items yet
      }
//--------------------------------------------------------------
   public void push(long j)    // put item on top of stack
      {
      stackArray[++top] = j;     // increment top, insert item
      }
//--------------------------------------------------------------
   public long pop()           // take item from top of stack
      {
      return stackArray[top--];  // access item, decrement top
      }
//--------------------------------------------------------------
   public long peek()          // peek at top of stack
      {
      return stackArray[top];
      }
//--------------------------------------------------------------
   public boolean isEmpty()    // true if stack is empty
      {
      return (top == -1);
      }
//--------------------------------------------------------------
   public boolean isFull()     // true if stack is full
      {
      return (top == maxSize-1);
      }
//--------------------------------------------------------------
   }  // end class StackX
////////////////////////////////////////////////////////////////
class StackApp
   {
   public static void main(String[] args)
      {
      StackX theStack = new StackX(10);  // make new stack
      theStack.push(20);               // push items onto stack
      theStack.push(40);
      theStack.push(60);
      theStack.push(80);

      while( !theStack.isEmpty() )     // until it's empty,
         {                             // delete item from stack
         long value = theStack.pop();
         System.out.print(value);      // display it
         System.out.print(" ");
         }  // end while
      System.out.println("");
      }  // end main()
   }  // end class StackApp
////////////////////////////////////////////////////////////////
// Queue.java
// demonstrates queue
// to run this program: C>java QueueApp
////////////////////////////////////////////////////////////////
class Queue
   {
   private int maxSize;
   private long[] queArray;
   private int front;
   private int rear;
   private int nItems;
//--------------------------------------------------------------
   public Queue(int s)          // constructor
      {
      maxSize = s;
      queArray = new long[maxSize];
      front = 0;
      rear = -1;
      nItems = 0;
      }
//--------------------------------------------------------------
   public void insert(long j)   // put item at rear of queue
      {
      if(rear == maxSize-1)         // deal with wraparound
         rear = -1;
      queArray[++rear] = j;         // increment rear and insert
      nItems++;                     // one more item
      }
//--------------------------------------------------------------
   public long remove()         // take item from front of queue
      {
      long temp = queArray[front++]; // get value and incr front
      if(front == maxSize)           // deal with wraparound
         front = 0;
      nItems--;                      // one less item
      return temp;
      }
//--------------------------------------------------------------
   public long peekFront()      // peek at front of queue
      {
      return queArray[front];
      }
//--------------------------------------------------------------
   public boolean isEmpty()    // true if queue is empty
      {
      return (nItems==0);
      }
//--------------------------------------------------------------
   public boolean isFull()     // true if queue is full
      {
      return (nItems==maxSize);
      }
//--------------------------------------------------------------
   public int size()           // number of items in queue
      {
      return nItems;
      }
//--------------------------------------------------------------
   }  // end class Queue
////////////////////////////////////////////////////////////////
class QueueApp
   {
   public static void main(String[] args)
      {
      Queue theQueue = new Queue(5);  // queue holds 5 items

      theQueue.insert(10);            // insert 4 items
      theQueue.insert(20);
      theQueue.insert(30);
      theQueue.insert(40);

      theQueue.remove();              // remove 3 items
      theQueue.remove();              //    (10, 20, 30)
      theQueue.remove();

      theQueue.insert(50);            // insert 4 more items
      theQueue.insert(60);            //    (wraps around)
      theQueue.insert(70);
      theQueue.insert(80);

      while( !theQueue.isEmpty() )    // remove and display
         {                            //    all items
         long n = theQueue.remove();  // (40, 50, 60, 70, 80)
         System.out.print(n);
         System.out.print(" ");
         }
      System.out.println("");
      }  // end main()
   }  // end class QueueApp
////////////////////////////////////////////////////////////////
// linkList.java
// demonstrates linked list
// to run this program: C>java LinkListApp
////////////////////////////////////////////////////////////////
class Link
   {
   public int iData;              // data item
   public double dData;           // data item
   public Link next;              // next link in list
// -------------------------------------------------------------
   public Link(int id, double dd) // constructor
      {
      iData = id;                 // initialize data
      dData = dd;                 // ('next' is automatically
      }                           //  set to null)
// -------------------------------------------------------------
   public void displayLink()      // display ourself
      {
      System.out.print("{" + iData + ", " + dData + "} ");
      }
   }  // end class Link
////////////////////////////////////////////////////////////////
class LinkList
   {
   private Link first;            // ref to first link on list

// -------------------------------------------------------------
   public LinkList()              // constructor
      {
      first = null;               // no links on list yet
      }
// -------------------------------------------------------------
   public boolean isEmpty()       // true if list is empty
      {
      return (first==null);
      }
// -------------------------------------------------------------
                                  // insert at start of list
   public void insertFirst(int id, double dd)
      {                           // make new link
      Link newLink = new Link(id, dd);
      newLink.next = first;       // newLink --> old first
      first = newLink;            // first --> newLink
      }
// -------------------------------------------------------------
   public Link deleteFirst()      // delete first item
      {                           // (assumes list not empty)
      Link temp = first;          // save reference to link
      first = first.next;         // delete it: first-->old next
      return temp;                // return deleted link
      }
// -------------------------------------------------------------
   public void displayList()
      {
      System.out.print("List (first-->last): ");
      Link current = first;       // start at beginning of list
      while(current != null)      // until end of list,
         {
         current.displayLink();   // print data
         current = current.next;  // move to next link
         }
      System.out.println("");
      }
// -------------------------------------------------------------
   }  // end class LinkList
////////////////////////////////////////////////////////////////
class LinkListApp
   {
   public static void main(String[] args)
      {
      LinkList theList = new LinkList();  // make new list

      theList.insertFirst(22, 2.99);      // insert four items
      theList.insertFirst(44, 4.99);
      theList.insertFirst(66, 6.99);
      theList.insertFirst(88, 8.99);

      theList.displayList();              // display list

      while( !theList.isEmpty() )         // until it's empty,
         {
         Link aLink = theList.deleteFirst();   // delete link
         System.out.print("Deleted ");         // display it
         aLink.displayLink();
         System.out.println("");
         }
      theList.displayList();              // display list
      }  // end main()
   }  // end class LinkListApp
////////////////////////////////////////////////////////////////
 // doublyLinked.java
// demonstrates doubly-linked list
// to run this program: C>java DoublyLinkedApp
////////////////////////////////////////////////////////////////
class Link
   {
   public long dData;                 // data item
   public Link next;                  // next link in list
   public Link previous;              // previous link in list
// -------------------------------------------------------------
   public Link(long d)                // constructor
      { dData = d; }
// -------------------------------------------------------------
   public void displayLink()          // display this link
      { System.out.print(dData + " "); }
// -------------------------------------------------------------
   }  // end class Link
////////////////////////////////////////////////////////////////
class DoublyLinkedList
   {
   private Link first;               // ref to first item
   private Link last;                // ref to last item
// -------------------------------------------------------------
   public DoublyLinkedList()         // constructor
      {
      first = null;                  // no items on list yet
      last = null;
      }
// -------------------------------------------------------------
   public boolean isEmpty()          // true if no links
      { return first==null; }
// -------------------------------------------------------------
   public void insertFirst(long dd)  // insert at front of list
      {
      Link newLink = new Link(dd);   // make new link

      if( isEmpty() )                // if empty list,
         last = newLink;             // newLink <-- last
      else
         first.previous = newLink;   // newLink <-- old first
      newLink.next = first;          // newLink --> old first
      first = newLink;               // first --> newLink
      }
// -------------------------------------------------------------
   public void insertLast(long dd)   // insert at end of list
      {
      Link newLink = new Link(dd);   // make new link
      if( isEmpty() )                // if empty list,
         first = newLink;            // first --> newLink
      else
         {
         last.next = newLink;        // old last --> newLink
         newLink.previous = last;    // old last <-- newLink
         }
      last = newLink;                // newLink <-- last
      }
// -------------------------------------------------------------
   public Link deleteFirst()         // delete first link
      {                              // (assumes non-empty list)
      Link temp = first;
      if(first.next == null)         // if only one item
         last = null;                // null <-- last
      else
         first.next.previous = null; // null <-- old next
      first = first.next;            // first --> old next
      return temp;
      }
// -------------------------------------------------------------
   public Link deleteLast()          // delete last link
      {                              // (assumes non-empty list)
      Link temp = last;
      if(first.next == null)         // if only one item
         first = null;               // first --> null
      else
         last.previous.next = null;  // old previous --> null
      last = last.previous;          // old previous <-- last
      return temp;
      }
// -------------------------------------------------------------
                                     // insert dd just after key
   public boolean insertAfter(long key, long dd)
      {                              // (assumes non-empty list)
      Link current = first;          // start at beginning
      while(current.dData != key)    // until match is found,
         {
         current = current.next;     // move to next link
         if(current == null)
            return false;            // didn't find it
         }
      Link newLink = new Link(dd);   // make new link

      if(current==last)              // if last link,
         {
         newLink.next = null;        // newLink --> null
         last = newLink;             // newLink <-- last
         }
      else                           // not last link,
         {
         newLink.next = current.next; // newLink --> old next
                                      // newLink <-- old next
         current.next.previous = newLink;
         }
      newLink.previous = current;    // old current <-- newLink
      current.next = newLink;        // old current --> newLink
      return true;                   // found it, did insertion
      }
// -------------------------------------------------------------
   public Link deleteKey(long key)   // delete item w/ given key
      {                              // (assumes non-empty list)
      Link current = first;          // start at beginning
      while(current.dData != key)    // until match is found,
         {
         current = current.next;     // move to next link
         if(current == null)
            return null;             // didn't find it
         }
      if(current==first)             // found it; first item?
         first = current.next;       // first --> old next
      else                           // not first
                                     // old previous --> old next
         current.previous.next = current.next;

      if(current==last)              // last item?
         last = current.previous;    // old previous <-- last
      else                           // not last
                                     // old previous <-- old next
         current.next.previous = current.previous;
      return current;                // return value
      }
// -------------------------------------------------------------
   public void displayForward()
      {
      System.out.print("List (first-->last): ");
      Link current = first;          // start at beginning
      while(current != null)         // until end of list,
         {
         current.displayLink();      // display data
         current = current.next;     // move to next link
         }
      System.out.println("");
      }
// -------------------------------------------------------------
   public void displayBackward()
      {
      System.out.print("List (last-->first): ");
      Link current = last;           // start at end
      while(current != null)         // until start of list,
         {
         current.displayLink();      // display data
         current = current.previous; // move to previous link
         }
      System.out.println("");
      }
// -------------------------------------------------------------
   }  // end class DoublyLinkedList
////////////////////////////////////////////////////////////////
class DoublyLinkedApp
   {
   public static void main(String[] args)
      {                             // make a new list
      DoublyLinkedList theList = new DoublyLinkedList();

      theList.insertFirst(22);      // insert at front
      theList.insertFirst(44);
      theList.insertFirst(66);

      theList.insertLast(11);       // insert at rear
      theList.insertLast(33);
      theList.insertLast(55);

      theList.displayForward();     // display list forward
      theList.displayBackward();    // display list backward

      theList.deleteFirst();        // delete first item
      theList.deleteLast();         // delete last item
      theList.deleteKey(11);        // delete item with key 11

      theList.displayForward();     // display list forward

      theList.insertAfter(22, 77);  // insert 77 after 22
      theList.insertAfter(33, 88);  // insert 88 after 33

      theList.displayForward();     // display list forward
      }  // end main()
   }  // end class DoublyLinkedApp
////////////////////////////////////////////////////////////////
// tree.java
// demonstrates binary tree
// to run this program: C>java TreeApp
import java.io.*;
import java.util.*;               // for Stack class
////////////////////////////////////////////////////////////////
class Node
   {
   public int iData;              // data item (key)
   public double dData;           // data item
   public Node leftChild;         // this node's left child
   public Node rightChild;        // this node's right child

   public void displayNode()      // display ourself
      {
      System.out.print('{');
      System.out.print(iData);
      System.out.print(", ");
      System.out.print(dData);
      System.out.print("} ");
      }
   }  // end class Node
////////////////////////////////////////////////////////////////
class Tree
   {
   private Node root;             // first node of tree

// -------------------------------------------------------------
   public Tree()                  // constructor
      { root = null; }            // no nodes in tree yet
// -------------------------------------------------------------
   public Node find(int key)      // find node with given key
      {                           // (assumes non-empty tree)
      Node current = root;               // start at root
      while(current.iData != key)        // while no match,
         {
         if(key < current.iData)         // go left?
            current = current.leftChild;
         else                            // or go right?
            current = current.rightChild;
         if(current == null)             // if no child,
            return null;                 // didn't find it
         }
      return current;                    // found it
      }  // end find()
// -------------------------------------------------------------
   public void insert(int id, double dd)
      {
      Node newNode = new Node();    // make new node
      newNode.iData = id;           // insert data
      newNode.dData = dd;
      if(root==null)                // no node in root
         root = newNode;
      else                          // root occupied
         {
         Node current = root;       // start at root
         Node parent;
         while(true)                // (exits internally)
            {
            parent = current;
            if(id < current.iData)  // go left?
               {
               current = current.leftChild;
               if(current == null)  // if end of the line,
                  {                 // insert on left
                  parent.leftChild = newNode;
                  return;
                  }
               }  // end if go left
            else                    // or go right?
               {
               current = current.rightChild;
               if(current == null)  // if end of the line
                  {                 // insert on right
                  parent.rightChild = newNode;
                  return;
                  }
               }  // end else go right
            }  // end while
         }  // end else not root
      }  // end insert()
// -------------------------------------------------------------
   public boolean delete(int key) // delete node with given key
      {                           // (assumes non-empty list)
      Node current = root;
      Node parent = root;
      boolean isLeftChild = true;

      while(current.iData != key)        // search for node
         {
         parent = current;
         if(key < current.iData)         // go left?
            {
            isLeftChild = true;
            current = current.leftChild;
            }
         else                            // or go right?
            {
            isLeftChild = false;
            current = current.rightChild;
            }
         if(current == null)             // end of the line,
            return false;                // didn't find it
         }  // end while
      // found node to delete

      // if no children, simply delete it
      if(current.leftChild==null &&
                                   current.rightChild==null)
         {
         if(current == root)             // if root,
            root = null;                 // tree is empty
         else if(isLeftChild)
            parent.leftChild = null;     // disconnect
         else                            // from parent
            parent.rightChild = null;
         }

      // if no right child, replace with left subtree
      else if(current.rightChild==null)
         if(current == root)
            root = current.leftChild;
         else if(isLeftChild)
            parent.leftChild = current.leftChild;
         else
            parent.rightChild = current.leftChild;

      // if no left child, replace with right subtree
      else if(current.leftChild==null)
         if(current == root)
            root = current.rightChild;
         else if(isLeftChild)
            parent.leftChild = current.rightChild;
         else
            parent.rightChild = current.rightChild;

      else  // two children, so replace with inorder successor
         {
         // get successor of node to delete (current)
         Node successor = getSuccessor(current);

         // connect parent of current to successor instead
         if(current == root)
            root = successor;
         else if(isLeftChild)
            parent.leftChild = successor;
         else
            parent.rightChild = successor;

         // connect successor to current's left child
         successor.leftChild = current.leftChild;
         }  // end else two children
      // (successor cannot have a left child)
      return true;                                // success
      }  // end delete()
// -------------------------------------------------------------
   // returns node with next-highest value after delNode
   // goes to right child, then right child's left descendents
   private Node getSuccessor(Node delNode)
      {
      Node successorParent = delNode;
      Node successor = delNode;
      Node current = delNode.rightChild;   // go to right child
      while(current != null)               // until no more
         {                                 // left children,
         successorParent = successor;
         successor = current;
         current = current.leftChild;      // go to left child
         }
                                           // if successor not
      if(successor != delNode.rightChild)  // right child,
         {                                 // make connections
         successorParent.leftChild = successor.rightChild;
         successor.rightChild = delNode.rightChild;
         }
      return successor;
      }
// -------------------------------------------------------------
   public void traverse(int traverseType)
      {
      switch(traverseType)
         {
         case 1: System.out.print("/nPreorder traversal: ");
                 preOrder(root);
                 break;
         case 2: System.out.print("/nInorder traversal:  ");
                 inOrder(root);
                 break;
         case 3: System.out.print("/nPostorder traversal: ");
                 postOrder(root);
                 break;
         }
      System.out.println();
      }
// -------------------------------------------------------------
   private void preOrder(Node localRoot)
      {
      if(localRoot != null)
         {
         System.out.print(localRoot.iData + " ");
         preOrder(localRoot.leftChild);
         preOrder(localRoot.rightChild);
         }
      }
// -------------------------------------------------------------
   private void inOrder(Node localRoot)
      {
      if(localRoot != null)
         {
         inOrder(localRoot.leftChild);
         System.out.print(localRoot.iData + " ");
         inOrder(localRoot.rightChild);
         }
      }
// -------------------------------------------------------------
   private void postOrder(Node localRoot)
      {
      if(localRoot != null)
         {
         postOrder(localRoot.leftChild);
         postOrder(localRoot.rightChild);
         System.out.print(localRoot.iData + " ");
         }
      }
// -------------------------------------------------------------
   public void displayTree()
      {
      Stack globalStack = new Stack();
      globalStack.push(root);
      int nBlanks = 32;
      boolean isRowEmpty = false;
      System.out.println(
      "......................................................");
      while(isRowEmpty==false)
         {
         Stack localStack = new Stack();
         isRowEmpty = true;

         for(int j=0; j<nBlanks; j++)
            System.out.print(' ');

         while(globalStack.isEmpty()==false)
            {
            Node temp = (Node)globalStack.pop();
            if(temp != null)
               {
               System.out.print(temp.iData);
               localStack.push(temp.leftChild);
               localStack.push(temp.rightChild);

               if(temp.leftChild != null ||
                                   temp.rightChild != null)
                  isRowEmpty = false;
               }
            else
               {
               System.out.print("--");
               localStack.push(null);
               localStack.push(null);
               }
            for(int j=0; j<nBlanks*2-2; j++)
               System.out.print(' ');
            }  // end while globalStack not empty
         System.out.println();
         nBlanks /= 2;
         while(localStack.isEmpty()==false)
            globalStack.push( localStack.pop() );
         }  // end while isRowEmpty is false
      System.out.println(
      "......................................................");
      }  // end displayTree()
// -------------------------------------------------------------
   }  // end class Tree
////////////////////////////////////////////////////////////////
class TreeApp
   {
   public static void main(String[] args) throws IOException
      {
      int value;
      Tree theTree = new Tree();

      theTree.insert(50, 1.5);
      theTree.insert(25, 1.2);
      theTree.insert(75, 1.7);
      theTree.insert(12, 1.5);
      theTree.insert(37, 1.2);
      theTree.insert(43, 1.7);
      theTree.insert(30, 1.5);
      theTree.insert(33, 1.2);
      theTree.insert(87, 1.7);
      theTree.insert(93, 1.5);
      theTree.insert(97, 1.5);

      while(true)
         {
         System.out.print("Enter first letter of show, ");
         System.out.print("insert, find, delete, or traverse: ");
         int choice = getChar();
         switch(choice)
            {
            case 's':
               theTree.displayTree();
               break;
            case 'i':
               System.out.print("Enter value to insert: ");
               value = getInt();
               theTree.insert(value, value + 0.9);
               break;
            case 'f':
               System.out.print("Enter value to find: ");
               value = getInt();
               Node found = theTree.find(value);
               if(found != null)
                  {
                  System.out.print("Found: ");
                  found.displayNode();
                  System.out.print("/n");
                  }
               else
                  System.out.print("Could not find ");
                  System.out.print(value + '/n');
               break;
            case 'd':
               System.out.print("Enter value to delete: ");
               value = getInt();
               boolean didDelete = theTree.delete(value);
               if(didDelete)
                  System.out.print("Deleted " + value + '/n');
               else
                  System.out.print("Could not delete ");
                  System.out.print(value + '/n');
               break;
            case 't':
               System.out.print("Enter type 1, 2 or 3: ");
               value = getInt();
               theTree.traverse(value);
               break;
            default:
               System.out.print("Invalid entry/n");
            }  // end switch
         }  // end while
      }  // end main()
// -------------------------------------------------------------
   public static String getString() throws IOException
      {
      InputStreamReader isr = new InputStreamReader(System.in);
      BufferedReader br = new BufferedReader(isr);
      String s = br.readLine();
      return s;
      }
// -------------------------------------------------------------
   public static char getChar() throws IOException
      {
      String s = getString();
      return s.charAt(0);
      }
//-------------------------------------------------------------
   public static int getInt() throws IOException
      {
      String s = getString();
      return Integer.parseInt(s);
      }
// -------------------------------------------------------------
   }  // end class TreeApp
////////////////////////////////////////////////////////////////