Inital commitHEADmaster

1 files changed, 164 insertions, 0 deletions

diff --git a/labs/lab04_recurionll/RecursionLinkedList.java b/labs/lab04_recurionll/RecursionLinkedList.java
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+++ b/labs/lab04_recurionll/RecursionLinkedList.java
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+
+public class RecursionLinkedList
+{
+	private Node firstNode;
+	private int numberOfEntries;
+	
+	public RecursionLinkedList()
+	{
+		firstNode = null;
+		numberOfEntries = 0;
+	}
+	
+	public void add(int aData)
+	{
+		if(numberOfEntries == 0)
+		{
+			firstNode = new Node(aData);
+		}
+		else
+		{
+			firstNode = new Node(aData, firstNode);
+		}
+		
+		numberOfEntries++;
+	}
+	
+	/**
+	 * boolean contains(int aData)
+	 * 
+	 * See whether this RecursionLinkedList contains aData
+	 * @param aData  a data to be located
+	 * @return true if this RecursionLinkedList contains aData,
+	 *         or false otherwise.
+	 */
+	public boolean contains(int aData)
+	{
+		return containsHelper(firstNode,aData);
+	}
+	private boolean containsHelper(Node thisnode, int aData)
+	{
+		if(thisnode == null)
+		{
+			return false;
+		}
+		else if(thisnode.data == aData)
+		{
+			return true;
+		}
+		else
+		{
+			return containsHelper(thisnode.next, aData);
+		}
+	}
+	
+	/**
+	 * int getFrequencyOf(int aData)
+	 * 
+	 * Counts the number of times a given data appears in this
+	 * RecursionLinkedList.
+	 * 
+	 * @param aData  the data to be counted
+	 * @return the number of times aData appears in this RecursionLinkedList
+	 */
+	public int getFrequencyOf(int aData)
+	{
+		return getFrequencyOfHelper(firstNode,aData);
+	}
+	private int getFrequencyOfHelper(Node thisnode, int aData)
+	{
+		if(thisnode == null)
+		{
+			return 0;
+		}
+		else if(thisnode.data == aData)
+		{
+			return getFrequencyOfHelper(thisnode.next, aData) + 1;
+		}
+		else
+		{
+			return getFrequencyOfHelper(thisnode.next, aData);
+		}
+	}
+	
+	/**
+	 * String toString()
+	 * 
+	 * Return a string representation of this RecursionLinkedList. For example,
+	 * if this RecursionLinkedList contains 1, 2, 3, 5, 2 and 3 from the first
+	 * index to the last index, the returned string should be
+	 * "[1,2,3,5,2,3]"
+	 * @return the string representation of this RecursionLinkedList.
+	 */
+	public String toString()
+	{
+		return "[" + firstNode.data + toStringHelper(firstNode.next) + "]";
+	}
+	private String toStringHelper(Node thisnode)
+	{
+		if(thisnode == null)
+		{
+			return "";
+		}
+		else
+		{
+			return "," + thisnode.data + toStringHelper(thisnode.next);
+		}
+	}
+	/**
+	 * int getIndexOf(int aData)
+	 * 
+	 * Return the index of the first aData where the first index of
+	 * the first item in this RecursionLinkedList is 0.
+	 * 
+	 * @param aData  the data to be located
+	 * @return the index of the first aData.
+	 */
+	public int getIndexOf(int aData)
+	{
+		int p = getIndexOfHelper(firstNode,aData);
+		/*
+		if(p==numberOfEntries+1)
+		{
+			return -1;
+		}
+		else
+		{
+			return p;
+		}
+		*/
+		return p==numberOfEntries+1?-1:p;
+	}
+	private int getIndexOfHelper(Node thisnode, int aData)
+	{
+		if(thisnode == null)
+		{
+			return 1;
+		}
+		else if(thisnode.data == aData)
+		{
+			return 0;
+		}
+		else
+		{
+			return getIndexOfHelper(thisnode.next,aData) + 1;
+		}
+	}
+		
+	private class Node
+	{
+		private int data;
+		private Node next;
+		
+		private Node(int aData, Node nextNode)
+		{
+			data = aData;
+			next = nextNode;
+		}
+		
+		private Node(int aData)
+		{
+			this(aData, null);
+		}
+	}
+}