标签：style blog http java color 使用
1：数据抽象
概念：
抽象数据类型，是一种能够对使用者隐藏数据表示的数据类型，抽象数据类型之所以重要，是因为他在程序设计上支持封装。
本节目标：本节将介绍三种抽象类型，用java实现，背包，堆栈，队列等最简单的数据结构。
import java.util.Iterator; import java.util.NoSuchElementException; /**
bag数据结构的实现 后进先出 不支持删除元素
*/ public class Bag<Item> implements Iterable<Item> { private int N; private Node<Item> first; // helper linked list class private static class Node<Item> { private Item item; private Node<Item> next; } /** * Is this bag empty? * * @return true if this bag is empty; false otherwise */ public boolean isEmpty() { return first == null; } /** * Returns the number of items in this bag. * * @return the number of items in this bag */ public int size() { return N; } /** * Adds the item to this bag. * * @param item the item to add to this bag */ public void add(Item item) { Node<Item> oldfirst = first; first = new Node<Item>(); first.item = item; first.next = oldfirst; N++; } /** * Initializes an empty bag. */ public Bag() { N = 0; first = null; } @Override public Iterator<Item> iterator() { return new ListIterator<Item>(first); } private class ListIterator<Item> implements Iterator<Item> { private Node<Item> current; public ListIterator(Node<Item> first) { current = first; } @Override public boolean hasNext() { return current != null; } @Override public Item next() { if (!hasNext()) throw new NoSuchElementException(); Item item = current.item; current = current.next; return item; } @Override public void remove() { throw new UnsupportedOperationException(); } } }
先进先出的队列结构，FIFO。Code实现
package com.luochuang.demo.stdlib; import org.w3c.dom.ls.LSException; import java.util.Iterator; import java.util.NoSuchElementException; public class Queue<Item> implements Iterable<Item> { private int N;// number of element on queue private Node<Item> first;// beginning of queue private Node<Item> last;// end of queue public class Node<Item> { private Node<Item> next; private Item item; } public Item peek() { if (isEmpty()) { throw new NoSuchElementException(); } return first.item; } /** * add item to queue * * @param item the item to add */ public void enQueue(Item item) { Node<Item> oldlast = last; last = new Node<Item>(); last.item = item; last.next = null; if (isEmpty()) { first = last; } else { oldlast.next = last; } N++; } /** * Removes and returns the item on this queue that was least recently added. * * @return the item on this queue that was least recently added * @throws java.util.NoSuchElementException if this queue is empty */ public Item deQueue() { if (isEmpty()) { throw new NoSuchElementException(); } Item item = first.item; first = first.next; N--; if (isEmpty()) { last = null; } return item; } /** * is this queue empty? * * @return true if this queue is empty otherwise */ public boolean isEmpty() { return first == null; } /** * Returns the number of items in this queue. * * @return the number of items in this queue */ public int size() { return N; } /** * Initializes an empty queue. */ public Queue() { first = null; last = null; N = 0; } @Override public Iterator<Item> iterator() { return null; } public class ListIterator implements Iterator<Item> { private Node<Item> current; public ListIterator(Node<Item> first) { first = current; } @Override public boolean hasNext() { return current == null; } @Override public Item next() { if (!hasNext()) throw new NoSuchElementException(); Item item = current.item; current = current.next; return item; } @Override public void remove() { throw new UnsupportedOperationException(); } } }
package com.luochuang.demo.stdlib; import java.util.Iterator; import java.util.NoSuchElementException; public class Stack<Item> implements Iterable<Item> { private int N; private Node<Item> first; /** * Initializes an empty stack */ public Stack() { first = null; N = 0; } /** * Adds the item to this stack. * @param item the item to add */ public void push(Item item) { Node<Item> oldfirst = first; first = new Node<Item>(); first.item = item; first.next = oldfirst; N++; } /** * Removes and returns the item most recently added to this stack. * * @return the item most recently added * @throws java.util.NoSuchElementException if this stack is empty */ public Item pop() { if (isEmpty()) throw new NoSuchElementException("Stack underflow"); Item item = first.item; // save item to return first = first.next; // delete first node N--; return item; // return the saved item } /** * Returns (but does not remove) the item most recently added to this stack. * @return the item most recently added to this stack * @throws java.util.NoSuchElementException if this stack is empty */ public Item peek() { if (isEmpty()) throw new NoSuchElementException("Stack underflow"); return first.item; } public boolean isEmpty() { return first == null; } public int size() { return N; } private class Node<Item> { private Node<Item> next; private Item item; } /** * Returns a string representation of this stack. * @return the sequence of items in the stack in LIFO order, separated by spaces */ public String toString() { StringBuilder s = new StringBuilder(); for (Item item : this) s.append(item + " "); return s.toString(); } @Override public Iterator<Item> iterator() { return new ListIterator(first); } public class ListIterator implements Iterator<Item> { public Node<Item> current; public ListIterator(Node<Item> first) { first = current; } @Override public boolean hasNext() { return current == null; } @Override public Item next() { if (!hasNext()) { throw new NoSuchElementException(); } Item item = current.item; current = current.next; return item; } @Override public void remove() { throw new UnsupportedOperationException(); } } }
标签：style blog http java color 使用
原文地址：http://www.cnblogs.com/luochuanghero/p/3844793.html
