/*
 * Copyright (c) 2007-2010 by The Broad Institute, Inc. and the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * This software is licensed under the terms of the GNU Lesser General Public License (LGPL), Version 2.1 which
 * is available at http://www.opensource.org/licenses/lgpl-2.1.php.
 *
 * THE SOFTWARE IS PROVIDED "AS IS." THE BROAD AND MIT MAKE NO REPRESENTATIONS OR WARRANTIES OF
 * ANY KIND CONCERNING THE SOFTWARE, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NONINFRINGEMENT, OR THE ABSENCE OF LATENT
 * OR OTHER DEFECTS, WHETHER OR NOT DISCOVERABLE.  IN NO EVENT SHALL THE BROAD OR MIT, OR THEIR
 * RESPECTIVE TRUSTEES, DIRECTORS, OFFICERS, EMPLOYEES, AND AFFILIATES BE LIABLE FOR ANY DAMAGES OF
 * ANY KIND, INCLUDING, WITHOUT LIMITATION, INCIDENTAL OR CONSEQUENTIAL DAMAGES, ECONOMIC
 * DAMAGES OR INJURY TO PROPERTY AND LOST PROFITS, REGARDLESS OF WHETHER THE BROAD OR MIT SHALL
 * BE ADVISED, SHALL HAVE OTHER REASON TO KNOW, OR IN FACT SHALL KNOW OF THE POSSIBILITY OF THE
 * FOREGOING.
 */
package edu.mit.broad.prodinfo.datastrutures;

import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * A Red-Black tree with intervals for keys.
 * Not thread-safe, and cannot be made so.
 *
 * @author tsharpe
 * @version $Revision: 51146 $
 */
public class IntervalTree<V>
{
	/**
	 * Return the number of intervals in the tree.
	 * @return The number of intervals.
	 */
	public int size()
	{
		return mRoot == null ? 0 : mRoot.getSize();
	}
	
	public boolean isEmpty () 
	{
		return size() == 0;
	}

	/**
	 * Remove all entries.
	 */
	public void clear()
	{
		mRoot = null;
	}

	/**
	 * Put a new interval into the tree (or update the value associated with an existing interval).
	 * If the interval is novel, the special sentinel value is returned.
	 * @param interval The interval.
	 * @param value The associated value.
	 * @return The old value associated with that interval, or the sentinel.
	 */
	public V put( Interval interval, V value )
	{
		return put(interval.getStart(),interval.getEnd(),value);
	}

	/**
	 * Put a new interval into the tree (or update the value associated with an existing interval).
	 * If the interval is novel, the special sentinel value is returned.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @param value The associated value.
	 * @return The old value associated with that interval, or the sentinel.
	 */
	@SuppressWarnings("null")
	public V put( int start, int end, V value )
	{
		if ( start > end )
			throw new IllegalArgumentException("Start cannot exceed end.");

		V result = mSentinel;

		if ( mRoot == null )
		{
			mRoot = new Node<V>(start,end,value);
		}
		else
		{
			Node<V> parent = null;
			Node<V> node = mRoot;
			int cmpVal = 0;

			while ( node != null )
			{
				parent = node; // last non-null node
				cmpVal = node.compare(start,end);
				if ( cmpVal == 0 )
				{
					break;
				}

				node = cmpVal < 0 ? node.getLeft() : node.getRight();
			}

			if ( cmpVal == 0 )
			{
				result = parent.setValue(value);
			}
			else
			{
				if ( cmpVal < 0 )
				{
					mRoot = parent.insertLeft(start,end,value,mRoot);
				}
				else
				{
					mRoot = parent.insertRight(start,end,value,mRoot);
				}
			}
		}

		return result;
	}

	/**
	 * Remove an interval from the tree.  If the interval does not exist in the tree the
	 * special sentinel value is returned.
	 * @param interval The interval to remove.
	 * @return The value associated with that interval, or the sentinel.
	 */
	public V remove( Interval interval )
	{
		return remove(interval.getStart(),interval.getEnd());
	}

	/**
	 * Remove an interval from the tree.  If the interval does not exist in the tree the
	 * special sentinel value is returned.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The value associated with that interval, or the sentinel.
	 */
	public V remove( int start, int end )
	{
		V result = mSentinel;
		Node<V> node = mRoot;

		while ( node != null )
		{
			int cmpVal = node.compare(start,end);
			if ( cmpVal == 0 )
			{
				result = node.getValue();
				mRoot = node.remove(mRoot);
				break;
			}

			node = cmpVal < 0 ? node.getLeft() : node.getRight();
		}

		return result;
	}

	/**
	 * Find an interval.
	 * @param interval The interval sought.
	 * @return The Node that represents that interval, or null.
	 */
	public Node<V> find( Interval interval )
	{
		return find(interval.getStart(),interval.getEnd());
	}

	/**
	 * Find an interval.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The Node that represents that interval, or null.
	 */
	public Node<V> find( int start, int end )
	{
		Node<V> node = mRoot;

		while ( node != null )
		{
			int cmpVal = node.compare(start,end);
			if ( cmpVal == 0 )
			{
				break;
			}

			node = cmpVal < 0 ? node.getLeft() : node.getRight();
		}

		return node;
	}

	/**
	 * Find the nth interval in the tree.
	 * @param idx The rank of the interval sought (from 0 to size()-1).
	 * @return The Node that represents the nth interval.
	 */
	public Node<V> findByIndex( int idx )
	{
		return Node.findByRank(mRoot,idx+1);
	}

	/**
	 * Find the rank of the specified interval.  If the specified interval is not in the
	 * tree, then -1 is returned.
	 * @param interval The interval for which the index is sought.
	 * @return The rank of that interval, or -1.
	 */
	public int getIndex( Interval interval )
	{
		return getIndex(interval.getStart(),interval.getEnd());
	}

	/**
	 * Find the rank of the specified interval.  If the specified interval is not in the
	 * tree, then -1 is returned.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The rank of that interval, or -1.
	 */
	public int getIndex( int start, int end )
	{
		return Node.getRank(mRoot,start,end) - 1;
	}

	/**
	 * Find the least interval in the tree.
	 * @return The earliest interval, or null if the tree is empty.
	 */
	public Node<V> min()
	{
		Node<V> result = null;
		Node<V> node = mRoot;

		while ( node != null )
		{
			result = node;
			node = node.getLeft();
		}

		return result;
	}

	/**
	 * Find the earliest interval in the tree greater than or equal to the specified interval.
	 * @param interval The interval sought. 
	 * @return The earliest >= interval, or null if there is none.
	 */
	public Node<V> min( Interval interval )
	{
		return min(interval.getStart(),interval.getEnd());
	}

	/**
	 * Find the earliest interval in the tree greater than or equal to the specified interval.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The earliest >= interval, or null if there is none.
	 */
	@SuppressWarnings("null")
	public Node<V> min( int start, int end )
	{
		Node<V> result = null;
		Node<V> node = mRoot;
		int cmpVal = 0;

		while ( node != null )
		{
			result = node;
			cmpVal = node.compare(start,end);
			if ( cmpVal == 0 )
			{
				break;
			}

			node = cmpVal < 0 ? node.getLeft() : node.getRight();
		}

		if ( cmpVal > 0 )
		{
			result = result.getNext();
		}

		return result;
	}

	/**
	 * Find the earliest interval in the tree that overlaps the specified interval.
	 * @param interval The interval sought. 
	 * @return The earliest overlapping interval, or null if there is none.
	 */
	public Node<V> minOverlapper( Interval interval )
	{
		return minOverlapper(interval.getStart(),interval.getEnd());
	}

	/**
	 * Find the earliest interval in the tree that overlaps the specified interval.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The earliest overlapping interval, or null if there is none.
	 */
	public Node<V> minOverlapper( int start, int end )
	{
		Node<V> result = null;
		Node<V> node = mRoot;

		if ( node != null && node.getMaxEnd() > start )
		{
			while ( true )
			{
				if ( node.getStart() < end && start < node.getEnd() )
				{ // this node overlaps.  there might be a lesser overlapper down the left sub-tree.
					// no need to consider the right sub-tree:  even if there's an overlapper, if won't be minimal
					result = node;
					node = node.getLeft();
					if ( node == null || node.getMaxEnd() <= start )
						break; // no left sub-tree or all nodes end too early
				}
				else
				{ // no overlap.  if there might be a left sub-tree overlapper, consider the left sub-tree.
					Node<V> left = node.getLeft();
					if ( left != null && left.getMaxEnd() > start )
					{
						node = left;
					}
					else
					{ // left sub-tree cannot contain an overlapper.  consider the right sub-tree.
						if ( node.getStart() >= end )
							break; // everything in the right sub-tree is past the end of the query interval

						node = node.getRight();
						if ( node == null || node.getMaxEnd() <= start )
							break; // no right sub-tree or all nodes end too early
					}
				}
			}
		}

		return result;
	}

	/**
	 * Find the greatest interval in the tree.
	 * @return The latest interval, or null if the tree is empty.
	 */
	public Node<V> max()
	{
		Node<V> result = null;
		Node<V> node = mRoot;

		while ( node != null )
		{
			result = node;
			node = node.getRight();
		}

		return result;
	}

	/**
	 * Find the latest interval in the tree less than or equal to the specified interval.
	 * @param interval The interval sought. 
	 * @return The latest <= interval, or null if there is none.
	 */
	public Node<V> max( Interval interval )
	{
		return max(interval.getStart(),interval.getEnd());
	}

	/**
	 * Find the latest interval in the tree less than or equal to the specified interval.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return The latest >= interval, or null if there is none.
	 */
	@SuppressWarnings("null")
	public Node<V> max( int start, int end )
	{
		Node<V> result = null;
		Node<V> node = mRoot;
		int cmpVal = 0;

		while ( node != null )
		{
			result = node;
			cmpVal = node.compare(start,end);
			if ( cmpVal == 0 )
			{
				break;
			}

			node = cmpVal < 0 ? node.getLeft() : node.getRight();
		}

		if ( cmpVal < 0 )
		{
			result = result.getPrev();
		}

		return result;
	}

	/**
	 * Return an iterator over the entire tree.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> iterator()
	{
		return new FwdIterator(min());
	}
	
	/**
	 * Return an iterator over the entire tree values
	 * @return An iterator
	 */
	public Iterator<V> valueIterator() 
	{
		return new ValuesIterator<V>(iterator());
	}

	/**
	 * Return an iterator over all intervals greater than or equal to the specified interval.
	 * @param interval The minimum interval.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> iterator( Interval interval )
	{
		return new FwdIterator(min(interval.getStart(),interval.getEnd()));
	}

	/**
	 * Return an iterator over all intervals greater than or equal to the specified interval.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> iterator( int start, int end )
	{
		return new FwdIterator(min(start,end));
	}

	/**
	 * Return an iterator over all intervals overlapping the specified range.
	 * @param start The range start.
	 * @param end The range end.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> overlappers( int start, int end )
	{
		return new OverlapIterator(start,end);
	}

	/**
	 * Return an iterator over the entire tree that returns intervals in reverse order.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> reverseIterator()
	{
		return new RevIterator(max());
	}

	/**
	 * Return an iterator over all intervals less than or equal to the specified interval, in reverse order.
	 * @param interval The maximum interval.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> reverseIterator( Interval interval )
	{
		return new RevIterator(max(interval.getStart(),interval.getEnd()));
	}

	/**
	 * Return an iterator over all intervals less than or equal to the specified interval, in reverse order.
	 * @param start The interval's start.
	 * @param end The interval's end.
	 * @return An iterator.
	 */
	public Iterator<Node<V>> reverseIterator( int start, int end )
	{
		return new RevIterator(max(start,end));
	}

	/**
	 * Get the special sentinel value that will be used to signal novelty when putting a new interval
	 * into the tree, or to signal "not found" when removing an interval.  This is null by default.
	 * @return The sentinel value.
	 */
	public V getSentinel()
	{
		return mSentinel;
	}

	/**
	 * Set the special sentinel value that will be used to signal novelty when putting a new interval
	 * into the tree, or to signal "not found" when removing an interval.
	 * @param sentinel The new sentinel value.
	 * @return The old sentinel value.
	 */
	public V setSentinel( V sentinel )
	{
		V result = mSentinel;
		mSentinel = sentinel;
		return result;
	}

	void removeNode( Node<V> node )
	{
		mRoot = node.remove(mRoot);
	}

	private Node<V> mRoot;
	private V mSentinel;

	public static class Node<V1>
	implements Interval
	{
		Node( int start, int end, V1 value )
		{
			mStart = start;
			mEnd = end;
			mValue = value;
			mSize = 1;
			mMaxEnd = mEnd;
			mIsBlack = true;
		}

		Node( Node<V1> parent, int start, int end, V1 value )
		{
			mParent = parent;
			mStart = start;
			mEnd = end;
			mValue = value;
			mMaxEnd = mEnd;
			mSize = 1;
		}

		public int getStart()
		{
			return mStart;
		}

		public int getEnd()
		{
			return mEnd;
		}

		public int getLength()
		{
			return mEnd - mStart;
		}

		public int getRelationship( Interval interval )
		{
			int result = 0;
			if ( mStart < interval.getStart() )
				result = Interval.HAS_LESSER_PART;
			if ( mEnd > interval.getEnd() )
				result |= Interval.HAS_GREATER_PART;
			if ( mStart < interval.getEnd() && interval.getStart() < mEnd )
				result |= Interval.HAS_OVERLAPPING_PART;
			return result;
		}

		public boolean isAdjacent( Interval interval )
		{
			return mStart == interval.getEnd() || mEnd == interval.getStart();
		}

		public V1 getValue()
		{
			return mValue;
		}

		public V1 setValue( V1 value )
		{
			V1 result = mValue;
			mValue = value;
			return result;
		}

		int getSize()
		{
			return mSize;
		}

		int getMaxEnd()
		{
			return mMaxEnd;
		}

		Node<V1> getLeft()
		{
			return mLeft;
		}

		Node<V1> insertLeft( int start, int end, V1 value, Node<V1> root )
		{
			mLeft = new Node<V1>(this,start,end,value);
			return insertFixup(mLeft,root);
		}

		Node<V1> getRight()
		{
			return mRight;
		}

		Node<V1> insertRight( int start, int end, V1 value, Node<V1> root )
		{
			mRight = new Node<V1>(this,start,end,value);
			return insertFixup(mRight,root);
		}

		public Node<V1> getNext()
		{
			Node<V1> result;

			if ( mRight != null )
			{
				result = mRight;
				while ( result.mLeft != null )
				{
					result = result.mLeft;
				}
			}
			else
			{
				Node<V1> node = this;
				result = mParent;
				while ( result != null && node == result.mRight )
				{
					node = result;
					result = result.mParent;
				}
			}

			return result;
		}

		public Node<V1> getPrev()
		{
			Node<V1> result;

			if ( mLeft != null )
			{
				result = mLeft;
				while ( result.mRight != null )
				{
					result = result.mRight;
				}
			}
			else
			{
				Node<V1> node = this;
				result = mParent;
				while ( result != null && node == result.mLeft )
				{
					node = result;
					result = result.mParent;
				}
			}

			return result;
		}

		boolean wasRemoved()
		{
			return mSize == 0;
		}

		Node<V1> remove( Node<V1> root )
		{
			if ( mSize == 0 )
			{
				throw new IllegalStateException("Entry was already removed.");
			}

			if ( mLeft == null )
			{
				if ( mRight == null )
				{ // no children
					if ( mParent == null )
					{
						root = null;
					}
					else if ( mParent.mLeft == this )
					{
						mParent.mLeft = null;
						fixup(mParent);

						if ( mIsBlack )
							root = removeFixup(mParent,null,root);
					}
					else
					{
						mParent.mRight = null;
						fixup(mParent);

						if ( mIsBlack )
							root = removeFixup(mParent,null,root);
					}
				}
				else
				{ // single child on right
					root = spliceOut(mRight,root);
				}
			}
			else if ( mRight == null )
			{ // single child on left
				root = spliceOut(mLeft,root);
			}
			else
			{ // two children
				Node<V1> next = getNext();
			root = next.remove(root);

			// put next into tree in same position as this, effectively removing this
			if ( (next.mParent = mParent) == null )
				root = next;
			else if ( mParent.mLeft == this )
				mParent.mLeft = next;
			else
				mParent.mRight = next;

			if ( (next.mLeft = mLeft) != null )
			{
				mLeft.mParent = next;
			}

			if ( (next.mRight = mRight) != null )
			{
				mRight.mParent = next;
			}

			next.mIsBlack = mIsBlack;
			next.mSize = mSize;
			}

			mSize = 0;
			return root;
		}

		// backwards comparison!  compares start+end to this.
		int compare( int start, int end )
		{
			int result = 0;

			if ( start > mStart )
				result = 1;
			else if ( start < mStart )
				result = -1;
			else if ( end > mEnd )
				result = 1;
			else if ( end < mEnd )
				result = -1;

			return result;
		}

		@SuppressWarnings("null")
		static <V1> Node<V1> getNextOverlapper( Node<V1> node, int start, int end )
		{
			do
			{
				Node<V1> nextNode = node.mRight;
				if ( nextNode != null && nextNode.mMaxEnd > start )
				{
					node = nextNode;
					while ( (nextNode = node.mLeft) != null && nextNode.mMaxEnd > start )
						node = nextNode;
				}
				else
				{
					nextNode = node;
					while ( (node = nextNode.mParent) != null && node.mRight == nextNode )
						nextNode = node;
				}

				if ( node != null && node.mStart >= end )
					node = null;
			}
			while ( node != null && !(node.mStart < end && start < node.mEnd) );

			return node;
		}

		static <V1> Node<V1> findByRank( Node<V1> node, int rank )
		{
			while ( node != null )
			{
				int nodeRank = node.getRank();
				if ( rank == nodeRank )
					break;

				if ( rank < nodeRank )
				{
					node = node.mLeft;
				}
				else
				{
					node = node.mRight;
					rank -= nodeRank;
				}
			}

			return node;
		}

		static <V1> int getRank( Node<V1> node, int start, int end )
		{
			int rank = 0;

			while ( node != null )
			{
				int cmpVal = node.compare(start,end);
				if ( cmpVal < 0 )
				{
					node = node.mLeft;
				}
				else
				{
					rank += node.getRank();
					if ( cmpVal == 0 )
						return rank; // EARLY RETURN!!!

						node = node.mRight;
				}
			}

			return 0;
		}

		private int getRank()
		{
			int result = 1;
			if ( mLeft != null )
				result = mLeft.mSize + 1;
			return result;
		}

		private Node<V1> spliceOut( Node<V1> child, Node<V1> root )
		{
			if ( (child.mParent = mParent) == null )
			{
				root = child;
				child.mIsBlack = true;
			}
			else
			{
				if ( mParent.mLeft == this )
					mParent.mLeft = child;
				else
					mParent.mRight = child;
				fixup(mParent);

				if ( mIsBlack )
					root = removeFixup(mParent,child,root);
			}

			return root;
		}

		private Node<V1> rotateLeft( Node<V1> root )
		{
			Node<V1> child = mRight;

			int childSize = child.mSize;
			child.mSize = mSize;
			mSize -= childSize;

			if ( (mRight = child.mLeft) != null )
			{
				mRight.mParent = this;
				mSize += mRight.mSize;
			}

			if ( (child.mParent = mParent) == null )
				root = child;
			else if ( this == mParent.mLeft )
				mParent.mLeft = child;
			else
				mParent.mRight = child;

			child.mLeft = this;
			mParent = child;

			setMaxEnd();
			child.setMaxEnd();

			return root;
		}

		private Node<V1> rotateRight( Node<V1> root )
		{
			Node<V1> child = mLeft;

			int childSize = child.mSize;
			child.mSize = mSize;
			mSize -= childSize;

			if ( (mLeft = child.mRight) != null )
			{
				mLeft.mParent = this;
				mSize += mLeft.mSize;
			}

			if ( (child.mParent = mParent) == null )
				root = child;
			else if ( this == mParent.mLeft )
				mParent.mLeft = child;
			else
				mParent.mRight = child;

			child.mRight = this;
			mParent = child;

			setMaxEnd();
			child.setMaxEnd();

			return root;
		}

		private void setMaxEnd()
		{
			mMaxEnd = mEnd;
			if ( mLeft != null )
				mMaxEnd = Math.max(mMaxEnd,mLeft.mMaxEnd);
			if ( mRight != null )
				mMaxEnd = Math.max(mMaxEnd,mRight.mMaxEnd);
		}

		private static <V1> void fixup( Node<V1> node )
		{
			do
			{
				node.mSize = 1;
				node.mMaxEnd = node.mEnd;
				if ( node.mLeft != null )
				{
					node.mSize += node.mLeft.mSize;
					node.mMaxEnd = node.mMaxEnd > node.mLeft.mMaxEnd  ? node.mMaxEnd : node.mLeft.mMaxEnd;
                                        //Math.max(node.mMaxEnd,node.mLeft.mMaxEnd);
				}
				if ( node.mRight != null )
				{
					node.mSize += node.mRight.mSize;
                                        node.mMaxEnd = node.mMaxEnd > node.mRight.mMaxEnd ? node.mMaxEnd : node.mRight.mMaxEnd;
					//node.mMaxEnd = Math.max(node.mMaxEnd,node.mRight.mMaxEnd);
				}
			}
			while ( (node = node.mParent) != null );
		}

		private static <V1> Node<V1> insertFixup( Node<V1> daughter, Node<V1> root )
		{
			Node<V1> mom = daughter.mParent;
			fixup(mom);

			while( mom != null && !mom.mIsBlack )
			{
				Node<V1> gramma = mom.mParent;
				Node<V1> auntie = gramma.mLeft;
				if ( auntie == mom )
				{
					auntie = gramma.mRight;
					if ( auntie != null && !auntie.mIsBlack )
					{
						mom.mIsBlack = true;
						auntie.mIsBlack = true;
						gramma.mIsBlack = false;
						daughter = gramma;
					}
					else
					{
						if ( daughter == mom.mRight )
						{
							root = mom.rotateLeft(root);
							mom = daughter;
						}
						mom.mIsBlack = true;
						gramma.mIsBlack = false;
						root = gramma.rotateRight(root);
						break;
					}
				}
				else
				{
					if ( auntie != null && !auntie.mIsBlack )
					{
						mom.mIsBlack = true;
						auntie.mIsBlack = true;
						gramma.mIsBlack = false;
						daughter = gramma;
					}
					else
					{
						if ( daughter == mom.mLeft )
						{
							root = mom.rotateRight(root);
							mom = daughter;
						}
						mom.mIsBlack = true;
						gramma.mIsBlack = false;
						root = gramma.rotateLeft(root);
						break;
					}
				}
				mom = daughter.mParent;
			}
			root.mIsBlack = true;
			return root;
		}

		private static <V1> Node<V1> removeFixup( Node<V1> parent, Node<V1> node, Node<V1> root )
		{
			do
			{
				if ( node == parent.mLeft )
				{
					Node<V1> sister = parent.mRight;
					if ( !sister.mIsBlack )
					{
						sister.mIsBlack = true;
						parent.mIsBlack = false;
						root = parent.rotateLeft(root);
						sister = parent.mRight;
					}
					if ( (sister.mLeft == null || sister.mLeft.mIsBlack) && (sister.mRight == null || sister.mRight.mIsBlack) )
					{
						sister.mIsBlack = false;
						node = parent;
					}
					else
					{
						if ( sister.mRight == null || sister.mRight.mIsBlack )
						{
							sister.mLeft.mIsBlack = true;
							sister.mIsBlack = false;
							root = sister.rotateRight(root);
							sister = parent.mRight;
						}
						sister.mIsBlack = parent.mIsBlack;
						parent.mIsBlack = true;
						sister.mRight.mIsBlack = true;
						root = parent.rotateLeft(root);
						node = root;
					}
				}
				else
				{
					Node<V1> sister = parent.mLeft;
					if ( !sister.mIsBlack )
					{
						sister.mIsBlack = true;
						parent.mIsBlack = false;
						root = parent.rotateRight(root);
						sister = parent.mLeft;
					}
					if ( (sister.mLeft == null || sister.mLeft.mIsBlack) && (sister.mRight == null || sister.mRight.mIsBlack) )
					{
						sister.mIsBlack = false;
						node = parent;
					}
					else
					{
						if ( sister.mLeft == null || sister.mLeft.mIsBlack )
						{
							sister.mRight.mIsBlack = true;
							sister.mIsBlack = false;
							root = sister.rotateLeft(root);
							sister = parent.mLeft;
						}
						sister.mIsBlack = parent.mIsBlack;
						parent.mIsBlack = true;
						sister.mLeft.mIsBlack = true;
						root = parent.rotateRight(root);
						node = root;
					}
				}
				parent = node.mParent;
			}
			while ( parent != null && node.mIsBlack );

			node.mIsBlack = true;
			return root;
		}

		private Node<V1> mParent;
		private Node<V1> mLeft;
		private Node<V1> mRight;
		private int mStart;
		private int mEnd;
		private V1 mValue;
		private int mSize;
		private int mMaxEnd;
		private boolean mIsBlack;
	}

	public class FwdIterator
	implements Iterator<Node<V>>
	{
		public FwdIterator( Node<V> node )
		{
			mNext = node;
		}

		public boolean hasNext()
		{
			return mNext != null;
		}

		public Node<V> next()
		{
			if ( mNext == null )
			{
				throw new NoSuchElementException("No next element.");
			}

			if ( mNext.wasRemoved() )
			{
				mNext = min(mNext.getStart(),mNext.getEnd());
				if ( mNext == null )
					throw new ConcurrentModificationException("Current element was removed, and there are no more elements.");
			}
			mLast = mNext;
			mNext = mNext.getNext();
			return mLast;
		}

		public void remove()
		{
			if ( mLast == null )
			{
				throw new IllegalStateException("No entry to remove.");
			}

			removeNode(mLast);
			mLast = null;
		}

		private Node<V> mNext;
		private Node<V> mLast;
	}

	public class RevIterator
	implements Iterator<Node<V>>
	{
		public RevIterator( Node<V> node )
		{
			mNext = node;
		}

		public boolean hasNext()
		{
			return mNext != null;
		}

		public Node<V> next()
		{
			if ( mNext == null )
				throw new NoSuchElementException("No next element.");
			if ( mNext.wasRemoved() )
			{
				mNext = max(mNext.getStart(),mNext.getEnd());
				if ( mNext == null )
					throw new ConcurrentModificationException("Current element was removed, and there are no more elements.");
			}
			mLast = mNext;
			mNext = mNext.getPrev();
			return mLast;
		}

		public void remove()
		{
			if ( mLast == null )
			{
				throw new IllegalStateException("No entry to remove.");
			}

			removeNode(mLast);
			mLast = null;
		}

		private Node<V> mNext;
		private Node<V> mLast;
	}

	public class OverlapIterator
	implements Iterator<Node<V>>
	{
		public OverlapIterator( int start, int end )
		{
			mNext = minOverlapper(start,end);
			mStart = start;
			mEnd = end;
		}

		public boolean hasNext()
		{
			return mNext != null;
		}

		public Node<V> next()
		{
			if ( mNext == null )
			{
				throw new NoSuchElementException("No next element.");
			}

			if ( mNext.wasRemoved() )
			{
				throw new ConcurrentModificationException("Current element was removed.");
			}

			mLast = mNext;
			mNext = Node.getNextOverlapper(mNext,mStart,mEnd);
			return mLast;
		}

		public void remove()
		{
			if ( mLast == null )
			{
				throw new IllegalStateException("No entry to remove.");
			}

			removeNode(mLast);
			mLast = null;
		}

		private Node<V> mNext;
		private Node<V> mLast;
		private int mStart;
		private int mEnd;
	}

	public static class ValuesIterator<V1>
	implements Iterator<V1>
	{
		public ValuesIterator( Iterator<Node<V1>> itr )
		{
			mItr = itr;
		}

		public boolean hasNext()
		{
			return mItr.hasNext();
		}

		public V1 next()
		{
			return mItr.next().getValue();
		}

		public void remove()
		{
			mItr.remove();
		}

		private Iterator<Node<V1>> mItr;
	}
}
