add Chapter_3_3

Author: gujiale

Chapter_3_3.java

@@ -0,0 +1,183 @@
+
+package practices.Chapter;
+
+
+/*
+	ʵÏÖMyLinkedListµÄcontainsÀý³Ì¡£
+*/
+
+class MyLinkedList<AnyType> implements Iterable<AnyType> {
+	private int theSize;
+	private int modCount =0;
+	private Node<AnyType> beginMarker;
+	private Node<AnyType> endMarker;
+	
+	/*Node½ÚµãÀà*/
+	private static class Node<AnyType> {
+		public Node(AnyType d, Node<AnyType> p, Node<AnyType> n) {
+			data = d;
+			prev = p;
+			next = n;
+		}
+		
+		public AnyType data;
+		public Node<AnyType> prev;
+		public Node<AnyType> next;
+	}
+	
+	public MyLinkedList() {
+		doClear();
+	}
+	
+	public void clear() {
+		doClear();
+	}
+	
+	private void doClear() {
+		beginMarker = new Node<AnyType>(null, null, null);
+		endMarker = new Node<AnyType>(null, beginMarker, null);
+		beginMarker.next = endMarker;
+		
+		theSize = 0;
+		modCount++;
+	}
+	
+	public int size() {
+		return theSize;
+	}
+	
+	public boolean isEmpty() {
+		return size() == 0;
+	}
+	
+	public boolean add(AnyType x) {
+		add(size(), x); 
+		return true;
+	}
+	
+	public void add(int idx, AnyType x) {
+		addBefore(getNode(idx, 0, size()), x);
+	}
+	
+	public AnyType get(int idx) {
+		return getNode(idx).data;
+	}
+	
+	public AnyType set(int idx, AnyType newVal) {
+		Node<AnyType> p = getNode(idx);
+		AnyType oldVal = p.data;
+		p.data = newVal;
+		return oldVal;
+	}
+	
+	public AnyType remove(int idx) {
+		return remove( getNode(idx));
+	}
+	
+	private void addBefore(Node<AnyType>  p, AnyType x) {
+		Node<AnyType> newNode = new Node<>(x, p.prev, p);
+		newNode.prev.next = newNode;
+		p.prev = newNode;
+		theSize++;
+		modCount++;
+	}
+	
+	private AnyType remove(Node<AnyType> p) {
+		p.next.prev = p.prev;
+		p.prev.next = p.next;
+		theSize--;
+		modCount--;
+		return p.data;
+	}
+	
+	private Node<AnyType> getNode(int idx) {
+		return getNode(idx, 0, size() - 1);
+	}
+	
+	private Node<AnyType> getNode(int idx, int lower, int upper) {
+		Node<AnyType> p;
+		
+		if(idx < lower || idx > upper)
+			throw new IndexOutOfBoundsException();
+		
+		if (idx < size() / 2) {
+			p = beginMarker.next;
+			for(int i=0; i < idx; i++)
+				p = p.next;
+		}
+		else {
+			p = endMarker;
+			for(int i = size(); i>idx; i--)
+				p = p.prev;
+		}
+		
+		return p;
+	}
+	
+	public boolean contains(AnyType x) {
+		Node<AnyType> p = beginMarker.next;
+		while (p != endMarker && (!p.data.equals(x))) {
+			p = p.next;
+		}
+		
+		return p != endMarker;
+	}
+	
+	public java.util.Iterator<AnyType> iterator() {
+		return new LinkedListIterator();
+	}
+	
+	private class LinkedListIterator implements java.util.Iterator<AnyType> {
+		private Node<AnyType> current = beginMarker.next;
+		private int expectedModCount = modCount;
+		private boolean okToRemove = false;
+		
+		public boolean hasNext() {
+			return current != endMarker;
+		}
+		
+		public AnyType next(){
+			if (modCount != expectedModCount) 
+				throw new java.util.ConcurrentModificationException();
+			
+			
+			if (!hasNext()) 
+				throw new java.util.NoSuchElementException();
+			
+			AnyType nextItem = current.data;
+			current = current.next;
+			okToRemove = true;
+			return nextItem;
+			
+		}
+		
+		public void remove() {
+			if (modCount != expectedModCount)
+				throw new java.util.ConcurrentModificationException();
+			if (!okToRemove)
+				throw new IllegalStateException();
+			
+			MyLinkedList.this.remove(current.prev);
+			expectedModCount++;
+			okToRemove = false;
+		}
+	}
+}
+
+public class Chapter_3_3 {
+		
+	public static void main(String args[]) {
+		System.out.println("Chapter_3_3");
+		
+		MyLinkedList<String> list = new MyLinkedList();
+		list.add("aaa");
+		list.add("bbb");
+		list.add("ccc");
+		list.add("ddd");
+		list.add("eee");
+		list.add("fff");
+		
+		System.out.println(list.contains("ccc"));
+		System.out.println(list.contains("aab"));
+	}
+}