it.unimi.dsi/fastutil/8.3.0 : it/unimi/dsi/fastutil/shorts/Short2ShortAVLTreeMap.java

Short2ShortAVLTreeMap
http://fastutil.di.unimi.it/: fastutil extends the Java Collections Framework by providing type-specific maps, sets, lists and priority queues with a small memory footprint and fast access and insertion; provides also big (64-bit) arrays, sets and lists, and fast, practical I/O classes for binary and text files.
Apache License, Version 2.0
Sebastiano Vigna
/*
	* Copyright (C) 2002-2019 Sebastiano Vigna
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	*     http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
package it.unimi.dsi.fastutil.shorts;
import it.unimi.dsi.fastutil.objects.AbstractObjectSortedSet;
import it.unimi.dsi.fastutil.objects.ObjectBidirectionalIterator;
import it.unimi.dsi.fastutil.objects.ObjectListIterator;
import it.unimi.dsi.fastutil.objects.ObjectSortedSet;
import it.unimi.dsi.fastutil.shorts.ShortCollection;
import it.unimi.dsi.fastutil.shorts.AbstractShortCollection;
import it.unimi.dsi.fastutil.shorts.ShortIterator;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.NoSuchElementException;
import it.unimi.dsi.fastutil.shorts.ShortListIterator;
A type-specific AVL tree map with a fast, small-footprint implementation.
 The iterators provided by the views of this class are type-specific bidirectional
iterators. Moreover, the iterator returned by iterator() can be safely cast to a type-specific list
iterator. /**
 * A type-specific AVL tree map with a fast, small-footprint implementation.
 *
 * <p>
 * The iterators provided by the views of this class are type-specific
 * {@linkplain it.unimi.dsi.fastutil.BidirectionalIterator bidirectional
 * iterators}. Moreover, the iterator returned by {@code iterator()} can be
 * safely cast to a type-specific {@linkplain java.util.ListIterator list
 * iterator}.
 */
public class Short2ShortAVLTreeMap extends AbstractShort2ShortSortedMap implements java.io.Serializable, Cloneable {
	A reference to the root entry. /** A reference to the root entry. */
	protected transient Entry tree;
	Number of entries in this map. /** Number of entries in this map. */
	protected int count;
	The first key in this map. /** The first key in this map. */
	protected transient Entry firstEntry;
	The last key in this map. /** The last key in this map. */
	protected transient Entry lastEntry;
	Cached set of entries. /** Cached set of entries. */
	protected transient ObjectSortedSet<Short2ShortMap.Entry> entries;
	Cached set of keys. /** Cached set of keys. */
	protected transient ShortSortedSet keys;
	Cached collection of values. /** Cached collection of values. */
	protected transient ShortCollection values;
	The value of this variable remembers, after a put() or a remove(), whether the domain of the map has been modified.
/**
	 * The value of this variable remembers, after a {@code put()} or a
	 * {@code remove()}, whether the <em>domain</em> of the map has been modified.
	 */
	protected transient boolean modified;
	This map's comparator, as provided in the constructor. /** This map's comparator, as provided in the constructor. */
	protected Comparator<? super Short> storedComparator;
	This map's actual comparator; it may differ from storedComparator because it is always a type-specific comparator, so it could be derived from the former by wrapping. /**
	 * This map's actual comparator; it may differ from {@link #storedComparator}
	 * because it is always a type-specific comparator, so it could be derived from
	 * the former by wrapping.
	 */
	protected transient ShortComparator actualComparator;
	private static final long serialVersionUID = -7046029254386353129L;
	{
		allocatePaths();
	}
	Creates a new empty tree map.
/**
	 * Creates a new empty tree map.
	 */
	public Short2ShortAVLTreeMap() {
		tree = null;
		count = 0;
	}
	Generates the comparator that will be actually used.
 When a given Comparator is specified and stored in storedComparator, we must check whether it is type-specific. If it is so, we can used directly, and we store it in actualComparator. Otherwise, we adapt it using a helper static method. /**
	 * Generates the comparator that will be actually used.
	 *
	 * <p>
	 * When a given {@link Comparator} is specified and stored in
	 * {@link #storedComparator}, we must check whether it is type-specific. If it
	 * is so, we can used directly, and we store it in {@link #actualComparator}.
	 * Otherwise, we adapt it using a helper static method.
	 */
	private void setActualComparator() {
		actualComparator = ShortComparators.asShortComparator(storedComparator);
	}
	Creates a new empty tree map with the given comparator.
Params: c – 
           a (possibly type-specific) comparator./**
	 * Creates a new empty tree map with the given comparator.
	 *
	 * @param c
	 *            a (possibly type-specific) comparator.
	 */
	public Short2ShortAVLTreeMap(final Comparator<? super Short> c) {
		this();
		storedComparator = c;
		setActualComparator();
	}
	Creates a new tree map copying a given map.
Params: m –  a Map to be copied into the new tree map./**
	 * Creates a new tree map copying a given map.
	 *
	 * @param m
	 *            a {@link Map} to be copied into the new tree map.
	 */
	public Short2ShortAVLTreeMap(final Map<? extends Short, ? extends Short> m) {
		this();
		putAll(m);
	}
	Creates a new tree map copying a given sorted map (and its Comparator). 
Params: m –  a SortedMap to be copied into the new tree map./**
	 * Creates a new tree map copying a given sorted map (and its
	 * {@link Comparator}).
	 *
	 * @param m
	 *            a {@link SortedMap} to be copied into the new tree map.
	 */
	public Short2ShortAVLTreeMap(final SortedMap<Short, Short> m) {
		this(m.comparator());
		putAll(m);
	}
	Creates a new tree map copying a given map.
Params: m – 
           a type-specific map to be copied into the new tree map./**
	 * Creates a new tree map copying a given map.
	 *
	 * @param m
	 *            a type-specific map to be copied into the new tree map.
	 */
	public Short2ShortAVLTreeMap(final Short2ShortMap m) {
		this();
		putAll(m);
	}
	Creates a new tree map copying a given sorted map (and its Comparator). 
Params: m – 
           a type-specific sorted map to be copied into the new tree map./**
	 * Creates a new tree map copying a given sorted map (and its
	 * {@link Comparator}).
	 *
	 * @param m
	 *            a type-specific sorted map to be copied into the new tree map.
	 */
	public Short2ShortAVLTreeMap(final Short2ShortSortedMap m) {
		this(m.comparator());
		putAll(m);
	}
	Creates a new tree map using the elements of two parallel arrays and the
given comparator.
Params: k – 
           the array of keys of the new tree map.
v – 
           the array of corresponding values in the new tree map.
c – 
           a (possibly type-specific) comparator.
Throws: IllegalArgumentException –  if k and v have different lengths./**
	 * Creates a new tree map using the elements of two parallel arrays and the
	 * given comparator.
	 *
	 * @param k
	 *            the array of keys of the new tree map.
	 * @param v
	 *            the array of corresponding values in the new tree map.
	 * @param c
	 *            a (possibly type-specific) comparator.
	 * @throws IllegalArgumentException
	 *             if {@code k} and {@code v} have different lengths.
	 */
	public Short2ShortAVLTreeMap(final short[] k, final short v[], final Comparator<? super Short> c) {
		this(c);
		if (k.length != v.length)
			throw new IllegalArgumentException(
					"The key array and the value array have different lengths (" + k.length + " and " + v.length + ")");
		for (int i = 0; i < k.length; i++)
			this.put(k[i], v[i]);
	}
	Creates a new tree map using the elements of two parallel arrays.
Params: k – 
           the array of keys of the new tree map.
v – 
           the array of corresponding values in the new tree map.
Throws: IllegalArgumentException –  if k and v have different lengths./**
	 * Creates a new tree map using the elements of two parallel arrays.
	 *
	 * @param k
	 *            the array of keys of the new tree map.
	 * @param v
	 *            the array of corresponding values in the new tree map.
	 * @throws IllegalArgumentException
	 *             if {@code k} and {@code v} have different lengths.
	 */
	public Short2ShortAVLTreeMap(final short[] k, final short v[]) {
		this(k, v, null);
	}
	/*
	 * The following methods implements some basic building blocks used by all
	 * accessors. They are (and should be maintained) identical to those used in
	 * AVLTreeSet.drv.
	 *
	 * The put()/remove() code is derived from Ben Pfaff's GNU libavl
	 * (http://www.msu.edu/~pfaffben/avl/). If you want to understand what's going
	 * on, you should have a look at the literate code contained therein first.
	 */
	Compares two keys in the right way.
 This method uses the actualComparator if it is non-null. Otherwise, it resorts to primitive type comparisons or to compareTo(). 
Params: k1 – 
           the first key.
k2 – 
           the second key.
Returns: a number smaller than, equal to or greater than 0, as usual (i.e.,
        when k1 < k2, k1 = k2 or k1 > k2, respectively)./**
	 * Compares two keys in the right way.
	 *
	 * <p>
	 * This method uses the {@link #actualComparator} if it is non-{@code null}.
	 * Otherwise, it resorts to primitive type comparisons or to
	 * {@link Comparable#compareTo(Object) compareTo()}.
	 *
	 * @param k1
	 *            the first key.
	 * @param k2
	 *            the second key.
	 * @return a number smaller than, equal to or greater than 0, as usual (i.e.,
	 *         when k1 &lt; k2, k1 = k2 or k1 &gt; k2, respectively).
	 */

	final int compare(final short k1, final short k2) {
		return actualComparator == null ? (Short.compare((k1), (k2))) : actualComparator.compare(k1, k2);
	}
	Returns the entry corresponding to the given key, if it is in the tree; null, otherwise. 
Params: k – 
           the key to search for.
Returns: the corresponding entry, or null if no entry with the given key exists./**
	 * Returns the entry corresponding to the given key, if it is in the tree;
	 * {@code null}, otherwise.
	 *
	 * @param k
	 *            the key to search for.
	 * @return the corresponding entry, or {@code null} if no entry with the given
	 *         key exists.
	 */
	final Entry findKey(final short k) {
		Entry e = tree;
		int cmp;
		while (e != null && (cmp = compare(k, e.key)) != 0)
			e = cmp < 0 ? e.left() : e.right();
		return e;
	}
	Locates a key.
Params: k – 
           a key.
Returns: the last entry on a search for the given key; this will be the given
        key, if it present; otherwise, it will be either the smallest greater
        key or the greatest smaller key./**
	 * Locates a key.
	 *
	 * @param k
	 *            a key.
	 * @return the last entry on a search for the given key; this will be the given
	 *         key, if it present; otherwise, it will be either the smallest greater
	 *         key or the greatest smaller key.
	 */
	final Entry locateKey(final short k) {
		Entry e = tree, last = tree;
		int cmp = 0;
		while (e != null && (cmp = compare(k, e.key)) != 0) {
			last = e;
			e = cmp < 0 ? e.left() : e.right();
		}
		return cmp == 0 ? e : last;
	}
	This vector remembers the directions followed during the current insertion.
It suffices for about 2³² entries.
/**
	 * This vector remembers the directions followed during the current insertion.
	 * It suffices for about 2<sup>32</sup> entries.
	 */
	private transient boolean dirPath[];
	private void allocatePaths() {
		dirPath = new boolean[48];
	}
	Adds an increment to value currently associated with a key.
 Note that this method respects the default
return value semantics: when called with a key that does not currently appears in the map, the key will be associated with the default return value plus the given increment. 
Params: k – 
           the key.
incr – 
           the increment.
Returns: the old value, or the default
        return value if no value was present for the given key./**
	 * Adds an increment to value currently associated with a key.
	 *
	 * <p>
	 * Note that this method respects the {@linkplain #defaultReturnValue() default
	 * return value} semantics: when called with a key that does not currently
	 * appears in the map, the key will be associated with the default return value
	 * plus the given increment.
	 *
	 * @param k
	 *            the key.
	 * @param incr
	 *            the increment.
	 * @return the old value, or the {@linkplain #defaultReturnValue() default
	 *         return value} if no value was present for the given key.
	 */
	public short addTo(final short k, final short incr) {
		Entry e = add(k);
		final short oldValue = e.value;
		e.value += incr;
		return oldValue;
	}
	@Override
	public short put(final short k, final short v) {
		Entry e = add(k);
		final short oldValue = e.value;
		e.value = v;
		return oldValue;
	}
	Returns a node with key k in the balanced tree, creating one with defRetValue
if necessary.
Params: k – 
           the key
Returns: a node with key k. If a node with key k already exists, then that
        node is returned, otherwise a new node with defRetValue is created
        ensuring that the tree is balanced after creation of the node./**
	 * Returns a node with key k in the balanced tree, creating one with defRetValue
	 * if necessary.
	 *
	 * @param k
	 *            the key
	 * @return a node with key k. If a node with key k already exists, then that
	 *         node is returned, otherwise a new node with defRetValue is created
	 *         ensuring that the tree is balanced after creation of the node.
	 */
	private Entry add(final short k) {
		/*
		 * After execution of this method, modified is true iff a new entry has been
		 * inserted.
		 */
		modified = false;
		Entry e = null;
		if (tree == null) { // The case of the empty tree is treated separately.
			count++;
			e = tree = lastEntry = firstEntry = new Entry(k, defRetValue);
			modified = true;
		} else {
			Entry p = tree, q = null, y = tree, z = null, w = null;
			int cmp, i = 0;
			while (true) {
				if ((cmp = compare(k, p.key)) == 0) {
					return p;
				}
				if (p.balance() != 0) {
					i = 0;
					z = q;
					y = p;
				}
				if (dirPath[i++] = cmp > 0) {
					if (p.succ()) {
						count++;
						e = new Entry(k, defRetValue);
						modified = true;
						if (p.right == null)
							lastEntry = e;
						e.left = p;
						e.right = p.right;
						p.right(e);
						break;
					}
					q = p;
					p = p.right;
				} else {
					if (p.pred()) {
						count++;
						e = new Entry(k, defRetValue);
						modified = true;
						if (p.left == null)
							firstEntry = e;
						e.right = p;
						e.left = p.left;
						p.left(e);
						break;
					}
					q = p;
					p = p.left;
				}
			}
			p = y;
			i = 0;
			while (p != e) {
				if (dirPath[i])
					p.incBalance();
				else
					p.decBalance();
				p = dirPath[i++] ? p.right : p.left;
			}
			if (y.balance() == -2) {
				Entry x = y.left;
				if (x.balance() == -1) {
					w = x;
					if (x.succ()) {
						x.succ(false);
						y.pred(x);
					} else
						y.left = x.right;
					x.right = y;
					x.balance(0);
					y.balance(0);
				} else {
					assert x.balance() == 1;
					w = x.right;
					x.right = w.left;
					w.left = x;
					y.left = w.right;
					w.right = y;
					if (w.balance() == -1) {
						x.balance(0);
						y.balance(1);
					} else if (w.balance() == 0) {
						x.balance(0);
						y.balance(0);
					} else {
						x.balance(-1);
						y.balance(0);
					}
					w.balance(0);
					if (w.pred()) {
						x.succ(w);
						w.pred(false);
					}
					if (w.succ()) {
						y.pred(w);
						w.succ(false);
					}
				}
			} else if (y.balance() == +2) {
				Entry x = y.right;
				if (x.balance() == 1) {
					w = x;
					if (x.pred()) {
						x.pred(false);
						y.succ(x);
					} else
						y.right = x.left;
					x.left = y;
					x.balance(0);
					y.balance(0);
				} else {
					assert x.balance() == -1;
					w = x.left;
					x.left = w.right;
					w.right = x;
					y.right = w.left;
					w.left = y;
					if (w.balance() == 1) {
						x.balance(0);
						y.balance(-1);
					} else if (w.balance() == 0) {
						x.balance(0);
						y.balance(0);
					} else {
						x.balance(1);
						y.balance(0);
					}
					w.balance(0);
					if (w.pred()) {
						y.succ(w);
						w.pred(false);
					}
					if (w.succ()) {
						x.pred(w);
						w.succ(false);
					}
				}
			} else
				return e;
			if (z == null)
				tree = w;
			else {
				if (z.left == y)
					z.left = w;
				else
					z.right = w;
			}
		}
		return e;
	}
	Finds the parent of an entry.
Params: e – 
           a node of the tree.
Returns: the parent of the given node, or null for the root./**
	 * Finds the parent of an entry.
	 *
	 * @param e
	 *            a node of the tree.
	 * @return the parent of the given node, or {@code null} for the root.
	 */
	private Entry parent(final Entry e) {
		if (e == tree)
			return null;
		Entry x, y, p;
		x = y = e;
		while (true) {
			if (y.succ()) {
				p = y.right;
				if (p == null || p.left != e) {
					while (!x.pred())
						x = x.left;
					p = x.left;
				}
				return p;
			} else if (x.pred()) {
				p = x.left;
				if (p == null || p.right != e) {
					while (!y.succ())
						y = y.right;
					p = y.right;
				}
				return p;
			}
			x = x.left;
			y = y.right;
		}
	}
	/*
	 * After execution of this method, {@link #modified} is true iff an entry has
	 * been deleted.
	 */

	@Override
	public short remove(final short k) {
		modified = false;
		if (tree == null)
			return defRetValue;
		int cmp;
		Entry p = tree, q = null;
		boolean dir = false;
		final short kk = k;
		while (true) {
			if ((cmp = compare(kk, p.key)) == 0)
				break;
			else if (dir = cmp > 0) {
				q = p;
				if ((p = p.right()) == null)
					return defRetValue;
			} else {
				q = p;
				if ((p = p.left()) == null)
					return defRetValue;
			}
		}
		if (p.left == null)
			firstEntry = p.next();
		if (p.right == null)
			lastEntry = p.prev();
		if (p.succ()) {
			if (p.pred()) {
				if (q != null) {
					if (dir)
						q.succ(p.right);
					else
						q.pred(p.left);
				} else
					tree = dir ? p.right : p.left;
			} else {
				p.prev().right = p.right;
				if (q != null) {
					if (dir)
						q.right = p.left;
					else
						q.left = p.left;
				} else
					tree = p.left;
			}
		} else {
			Entry r = p.right;
			if (r.pred()) {
				r.left = p.left;
				r.pred(p.pred());
				if (!r.pred())
					r.prev().right = r;
				if (q != null) {
					if (dir)
						q.right = r;
					else
						q.left = r;
				} else
					tree = r;
				r.balance(p.balance());
				q = r;
				dir = true;
			} else {
				Entry s;
				while (true) {
					s = r.left;
					if (s.pred())
						break;
					r = s;
				}
				if (s.succ())
					r.pred(s);
				else
					r.left = s.right;
				s.left = p.left;
				if (!p.pred()) {
					p.prev().right = s;
					s.pred(false);
				}
				s.right = p.right;
				s.succ(false);
				if (q != null) {
					if (dir)
						q.right = s;
					else
						q.left = s;
				} else
					tree = s;
				s.balance(p.balance());
				q = r;
				dir = false;
			}
		}
		Entry y;
		while (q != null) {
			y = q;
			q = parent(y);
			if (!dir) {
				dir = q != null && q.left != y;
				y.incBalance();
				if (y.balance() == 1)
					break;
				else if (y.balance() == 2) {
					Entry x = y.right;
					assert x != null;
					if (x.balance() == -1) {
						Entry w;
						assert x.balance() == -1;
						w = x.left;
						x.left = w.right;
						w.right = x;
						y.right = w.left;
						w.left = y;
						if (w.balance() == 1) {
							x.balance(0);
							y.balance(-1);
						} else if (w.balance() == 0) {
							x.balance(0);
							y.balance(0);
						} else {
							assert w.balance() == -1;
							x.balance(1);
							y.balance(0);
						}
						w.balance(0);
						if (w.pred()) {
							y.succ(w);
							w.pred(false);
						}
						if (w.succ()) {
							x.pred(w);
							w.succ(false);
						}
						if (q != null) {
							if (dir)
								q.right = w;
							else
								q.left = w;
						} else
							tree = w;
					} else {
						if (q != null) {
							if (dir)
								q.right = x;
							else
								q.left = x;
						} else
							tree = x;
						if (x.balance() == 0) {
							y.right = x.left;
							x.left = y;
							x.balance(-1);
							y.balance(+1);
							break;
						}
						assert x.balance() == 1;
						if (x.pred()) {
							y.succ(true);
							x.pred(false);
						} else
							y.right = x.left;
						x.left = y;
						y.balance(0);
						x.balance(0);
					}
				}
			} else {
				dir = q != null && q.left != y;
				y.decBalance();
				if (y.balance() == -1)
					break;
				else if (y.balance() == -2) {
					Entry x = y.left;
					assert x != null;
					if (x.balance() == 1) {
						Entry w;
						assert x.balance() == 1;
						w = x.right;
						x.right = w.left;
						w.left = x;
						y.left = w.right;
						w.right = y;
						if (w.balance() == -1) {
							x.balance(0);
							y.balance(1);
						} else if (w.balance() == 0) {
							x.balance(0);
							y.balance(0);
						} else {
							assert w.balance() == 1;
							x.balance(-1);
							y.balance(0);
						}
						w.balance(0);
						if (w.pred()) {
							x.succ(w);
							w.pred(false);
						}
						if (w.succ()) {
							y.pred(w);
							w.succ(false);
						}
						if (q != null) {
							if (dir)
								q.right = w;
							else
								q.left = w;
						} else
							tree = w;
					} else {
						if (q != null) {
							if (dir)
								q.right = x;
							else
								q.left = x;
						} else
							tree = x;
						if (x.balance() == 0) {
							y.left = x.right;
							x.right = y;
							x.balance(+1);
							y.balance(-1);
							break;
						}
						assert x.balance() == -1;
						if (x.succ()) {
							y.pred(true);
							x.succ(false);
						} else
							y.left = x.right;
						x.right = y;
						y.balance(0);
						x.balance(0);
					}
				}
			}
		}
		modified = true;
		count--;
		return p.value;
	}
	@Override
	public boolean containsValue(final short v) {
		final ValueIterator i = new ValueIterator();
		short ev;
		int j = count;
		while (j-- != 0) {
			ev = i.nextShort();
			if (((ev) == (v)))
				return true;
		}
		return false;
	}
	@Override
	public void clear() {
		count = 0;
		tree = null;
		entries = null;
		values = null;
		keys = null;
		firstEntry = lastEntry = null;
	}
	This class represent an entry in a tree map.
 We use the only "metadata", i.e., info, to store information about balance, predecessor status and successor status. 

Note that since the class is recursive, it can be considered equivalently a
tree.
/**
	 * This class represent an entry in a tree map.
	 *
	 * <p>
	 * We use the only "metadata", i.e., {@link Entry#info}, to store information
	 * about balance, predecessor status and successor status.
	 *
	 * <p>
	 * Note that since the class is recursive, it can be considered equivalently a
	 * tree.
	 */
	private static final class Entry extends AbstractShort2ShortMap.BasicEntry implements Cloneable {
		If the bit in this mask is true, right points to a successor. /** If the bit in this mask is true, {@link #right} points to a successor. */
		private static final int SUCC_MASK = 1 << 31;
		If the bit in this mask is true, left points to a predecessor. /** If the bit in this mask is true, {@link #left} points to a predecessor. */
		private static final int PRED_MASK = 1 << 30;
		The bits in this mask hold the node balance info. You can get it just by
casting to byte.
/**
		 * The bits in this mask hold the node balance info. You can get it just by
		 * casting to byte.
		 */
		private static final int BALANCE_MASK = 0xFF;
		The pointers to the left and right subtrees. /** The pointers to the left and right subtrees. */
		Entry left, right;
		This integers holds different information in different bits (see SUCC_MASK, PRED_MASK and BALANCE_MASK). /**
		 * This integers holds different information in different bits (see
		 * {@link #SUCC_MASK}, {@link #PRED_MASK} and {@link #BALANCE_MASK}).
		 */
		int info;
		Entry() {
			super(((short) 0), ((short) 0));
		}
		Creates a new entry with the given key and value.
Params: k – 
           a key.
v – 
           a value./**
		 * Creates a new entry with the given key and value.
		 *
		 * @param k
		 *            a key.
		 * @param v
		 *            a value.
		 */
		Entry(final short k, final short v) {
			super(k, v);
			info = SUCC_MASK | PRED_MASK;
		}
		Returns the left subtree.
Returns: the left subtree (null if the left subtree is empty)./**
		 * Returns the left subtree.
		 *
		 * @return the left subtree ({@code null} if the left subtree is empty).
		 */
		Entry left() {
			return (info & PRED_MASK) != 0 ? null : left;
		}
		Returns the right subtree.
Returns: the right subtree (null if the right subtree is empty)./**
		 * Returns the right subtree.
		 *
		 * @return the right subtree ({@code null} if the right subtree is empty).
		 */
		Entry right() {
			return (info & SUCC_MASK) != 0 ? null : right;
		}
		Checks whether the left pointer is really a predecessor.
Returns: true if the left pointer is a predecessor./**
		 * Checks whether the left pointer is really a predecessor.
		 * 
		 * @return true if the left pointer is a predecessor.
		 */
		boolean pred() {
			return (info & PRED_MASK) != 0;
		}
		Checks whether the right pointer is really a successor.
Returns: true if the right pointer is a successor./**
		 * Checks whether the right pointer is really a successor.
		 * 
		 * @return true if the right pointer is a successor.
		 */
		boolean succ() {
			return (info & SUCC_MASK) != 0;
		}
		Sets whether the left pointer is really a predecessor.
Params: pred – 
           if true then the left pointer will be considered a predecessor./**
		 * Sets whether the left pointer is really a predecessor.
		 * 
		 * @param pred
		 *            if true then the left pointer will be considered a predecessor.
		 */
		void pred(final boolean pred) {
			if (pred)
				info |= PRED_MASK;
			else
				info &= ~PRED_MASK;
		}
		Sets whether the right pointer is really a successor.
Params: succ – 
           if true then the right pointer will be considered a successor./**
		 * Sets whether the right pointer is really a successor.
		 * 
		 * @param succ
		 *            if true then the right pointer will be considered a successor.
		 */
		void succ(final boolean succ) {
			if (succ)
				info |= SUCC_MASK;
			else
				info &= ~SUCC_MASK;
		}
		Sets the left pointer to a predecessor.
Params: pred – 
           the predecessr./**
		 * Sets the left pointer to a predecessor.
		 * 
		 * @param pred
		 *            the predecessr.
		 */
		void pred(final Entry pred) {
			info |= PRED_MASK;
			left = pred;
		}
		Sets the right pointer to a successor.
Params: succ – 
           the successor./**
		 * Sets the right pointer to a successor.
		 * 
		 * @param succ
		 *            the successor.
		 */
		void succ(final Entry succ) {
			info |= SUCC_MASK;
			right = succ;
		}
		Sets the left pointer to the given subtree.
Params: left – 
           the new left subtree./**
		 * Sets the left pointer to the given subtree.
		 * 
		 * @param left
		 *            the new left subtree.
		 */
		void left(final Entry left) {
			info &= ~PRED_MASK;
			this.left = left;
		}
		Sets the right pointer to the given subtree.
Params: right – 
           the new right subtree./**
		 * Sets the right pointer to the given subtree.
		 * 
		 * @param right
		 *            the new right subtree.
		 */
		void right(final Entry right) {
			info &= ~SUCC_MASK;
			this.right = right;
		}
		Returns the current level of the node.
Returns: the current level of this node./**
		 * Returns the current level of the node.
		 * 
		 * @return the current level of this node.
		 */
		int balance() {
			return (byte) info;
		}
		Sets the level of this node.
Params: level – 
           the new level of this node./**
		 * Sets the level of this node.
		 * 
		 * @param level
		 *            the new level of this node.
		 */
		void balance(int level) {
			info &= ~BALANCE_MASK;
			info |= (level & BALANCE_MASK);
		}
		Increments the level of this node. /** Increments the level of this node. */
		void incBalance() {
			info = info & ~BALANCE_MASK | ((byte) info + 1) & 0xFF;
		}
		Decrements the level of this node. /** Decrements the level of this node. */
		protected void decBalance() {
			info = info & ~BALANCE_MASK | ((byte) info - 1) & 0xFF;
		}
		Computes the next entry in the set order.
Returns: the next entry (null) if this is the last entry)./**
		 * Computes the next entry in the set order.
		 *
		 * @return the next entry ({@code null}) if this is the last entry).
		 */
		Entry next() {
			Entry next = this.right;
			if ((info & SUCC_MASK) == 0)
				while ((next.info & PRED_MASK) == 0)
					next = next.left;
			return next;
		}
		Computes the previous entry in the set order.
Returns: the previous entry (null) if this is the first entry)./**
		 * Computes the previous entry in the set order.
		 *
		 * @return the previous entry ({@code null}) if this is the first entry).
		 */
		Entry prev() {
			Entry prev = this.left;
			if ((info & PRED_MASK) == 0)
				while ((prev.info & SUCC_MASK) == 0)
					prev = prev.right;
			return prev;
		}
		@Override
		public short setValue(final short value) {
			final short oldValue = this.value;
			this.value = value;
			return oldValue;
		}
		@Override

		public Entry clone() {
			Entry c;
			try {
				c = (Entry) super.clone();
			} catch (CloneNotSupportedException cantHappen) {
				throw new InternalError();
			}
			c.key = key;
			c.value = value;
			c.info = info;
			return c;
		}
		@Override
		@SuppressWarnings("unchecked")
		public boolean equals(final Object o) {
			if (!(o instanceof Map.Entry))
				return false;
			Map.Entry<Short, Short> e = (Map.Entry<Short, Short>) o;
			return ((key) == ((e.getKey()).shortValue())) && ((value) == ((e.getValue()).shortValue()));
		}
		@Override
		public int hashCode() {
			return (key) ^ (value);
		}
		@Override
		public String toString() {
			return key + "=>" + value;
		}
		/*
		 * public void prettyPrint() { prettyPrint(0); }
		 * 
		 * public void prettyPrint(int level) { if (pred()) { for (int i = 0; i < level;
		 * i++) System.err.print("  "); System.err.println("pred: " + left); } else if
		 * (left != null) left.prettyPrint(level +1); for (int i = 0; i < level; i++)
		 * System.err.print("  "); System.err.println(key + "=" + value + " (" +
		 * balance() + ")"); if (succ()) { for (int i = 0; i < level; i++)
		 * System.err.print("  "); System.err.println("succ: " + right); } else if
		 * (right != null) right.prettyPrint(level + 1); }
		 */
	}
	/*
	 * public void prettyPrint() { System.err.println("size: " + count); if (tree !=
	 * null) tree.prettyPrint(); }
	 */

	@Override
	public boolean containsKey(final short k) {
		return findKey(k) != null;
	}
	@Override
	public int size() {
		return count;
	}
	@Override
	public boolean isEmpty() {
		return count == 0;
	}

	@Override
	public short get(final short k) {
		final Entry e = findKey(k);
		return e == null ? defRetValue : e.value;
	}
	@Override
	public short firstShortKey() {
		if (tree == null)
			throw new NoSuchElementException();
		return firstEntry.key;
	}
	@Override
	public short lastShortKey() {
		if (tree == null)
			throw new NoSuchElementException();
		return lastEntry.key;
	}
	An abstract iterator on the whole range.

This class can iterate in both directions on a threaded tree.
/**
	 * An abstract iterator on the whole range.
	 *
	 * <p>
	 * This class can iterate in both directions on a threaded tree.
	 */
	private class TreeIterator {
		The entry that will be returned by the next call to ListIterator.previous() (or null if no previous entry exists). /**
		 * The entry that will be returned by the next call to
		 * {@link java.util.ListIterator#previous()} (or {@code null} if no previous
		 * entry exists).
		 */
		Entry prev;
		The entry that will be returned by the next call to ListIterator.next() (or null if no next entry exists). /**
		 * The entry that will be returned by the next call to
		 * {@link java.util.ListIterator#next()} (or {@code null} if no next entry
		 * exists).
		 */
		Entry next;
		The last entry that was returned (or null if we did not iterate or used remove()). /**
		 * The last entry that was returned (or {@code null} if we did not iterate or
		 * used {@link #remove()}).
		 */
		Entry curr;
		The current index (in the sense of a ListIterator). Note that this value is not meaningful when this TreeIterator has been created using the nonempty constructor. /**
		 * The current index (in the sense of a {@link java.util.ListIterator}). Note
		 * that this value is not meaningful when this {@link TreeIterator} has been
		 * created using the nonempty constructor.
		 */
		int index = 0;
		TreeIterator() {
			next = firstEntry;
		}
		TreeIterator(final short k) {
			if ((next = locateKey(k)) != null) {
				if (compare(next.key, k) <= 0) {
					prev = next;
					next = next.next();
				} else
					prev = next.prev();
			}
		}
		public boolean hasNext() {
			return next != null;
		}
		public boolean hasPrevious() {
			return prev != null;
		}
		void updateNext() {
			next = next.next();
		}
		Entry nextEntry() {
			if (!hasNext())
				throw new NoSuchElementException();
			curr = prev = next;
			index++;
			updateNext();
			return curr;
		}
		void updatePrevious() {
			prev = prev.prev();
		}
		Entry previousEntry() {
			if (!hasPrevious())
				throw new NoSuchElementException();
			curr = next = prev;
			index--;
			updatePrevious();
			return curr;
		}
		public int nextIndex() {
			return index;
		}
		public int previousIndex() {
			return index - 1;
		}
		public void remove() {
			if (curr == null)
				throw new IllegalStateException();
			/*
			 * If the last operation was a next(), we are removing an entry that preceeds
			 * the current index, and thus we must decrement it.
			 */
			if (curr == prev)
				index--;
			next = prev = curr;
			updatePrevious();
			updateNext();
			Short2ShortAVLTreeMap.this.remove(curr.key);
			curr = null;
		}
		public int skip(final int n) {
			int i = n;
			while (i-- != 0 && hasNext())
				nextEntry();
			return n - i - 1;
		}
		public int back(final int n) {
			int i = n;
			while (i-- != 0 && hasPrevious())
				previousEntry();
			return n - i - 1;
		}
	}
	An iterator on the whole range.

This class can iterate in both directions on a threaded tree.
/**
	 * An iterator on the whole range.
	 *
	 * <p>
	 * This class can iterate in both directions on a threaded tree.
	 */
	private class EntryIterator extends TreeIterator implements ObjectListIterator<Short2ShortMap.Entry> {
		EntryIterator() {
		}
		EntryIterator(final short k) {
			super(k);
		}
		@Override
		public Short2ShortMap.Entry next() {
			return nextEntry();
		}
		@Override
		public Short2ShortMap.Entry previous() {
			return previousEntry();
		}
		@Override
		public void set(Short2ShortMap.Entry ok) {
			throw new UnsupportedOperationException();
		}
		@Override
		public void add(Short2ShortMap.Entry ok) {
			throw new UnsupportedOperationException();
		}
	}
	@Override
	public ObjectSortedSet<Short2ShortMap.Entry> short2ShortEntrySet() {
		if (entries == null)
			entries = new AbstractObjectSortedSet<Short2ShortMap.Entry>() {
				final Comparator<? super Short2ShortMap.Entry> comparator = (Comparator<Short2ShortMap.Entry>) (x,
						y) -> Short2ShortAVLTreeMap.this.actualComparator.compare(x.getShortKey(), y.getShortKey());
				@Override
				public Comparator<? super Short2ShortMap.Entry> comparator() {
					return comparator;
				}
				@Override
				public ObjectBidirectionalIterator<Short2ShortMap.Entry> iterator() {
					return new EntryIterator();
				}
				@Override
				public ObjectBidirectionalIterator<Short2ShortMap.Entry> iterator(final Short2ShortMap.Entry from) {
					return new EntryIterator(from.getShortKey());
				}
				@Override

				public boolean contains(final Object o) {
					if (!(o instanceof Map.Entry))
						return false;
					final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
					if (e.getKey() == null || !(e.getKey() instanceof Short))
						return false;
					if (e.getValue() == null || !(e.getValue() instanceof Short))
						return false;
					final Entry f = findKey(((Short) (e.getKey())).shortValue());
					return e.equals(f);
				}
				@Override

				public boolean remove(final Object o) {
					if (!(o instanceof Map.Entry))
						return false;
					final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
					if (e.getKey() == null || !(e.getKey() instanceof Short))
						return false;
					if (e.getValue() == null || !(e.getValue() instanceof Short))
						return false;
					final Entry f = findKey(((Short) (e.getKey())).shortValue());
					if (f == null || !((f.getShortValue()) == (((Short) (e.getValue())).shortValue())))
						return false;
					Short2ShortAVLTreeMap.this.remove(f.key);
					return true;
				}
				@Override
				public int size() {
					return count;
				}
				@Override
				public void clear() {
					Short2ShortAVLTreeMap.this.clear();
				}
				@Override
				public Short2ShortMap.Entry first() {
					return firstEntry;
				}
				@Override
				public Short2ShortMap.Entry last() {
					return lastEntry;
				}
				@Override
				public ObjectSortedSet<Short2ShortMap.Entry> subSet(Short2ShortMap.Entry from,
						Short2ShortMap.Entry to) {
					return subMap(from.getShortKey(), to.getShortKey()).short2ShortEntrySet();
				}
				@Override
				public ObjectSortedSet<Short2ShortMap.Entry> headSet(Short2ShortMap.Entry to) {
					return headMap(to.getShortKey()).short2ShortEntrySet();
				}
				@Override
				public ObjectSortedSet<Short2ShortMap.Entry> tailSet(Short2ShortMap.Entry from) {
					return tailMap(from.getShortKey()).short2ShortEntrySet();
				}
			};
		return entries;
	}
	An iterator on the whole range of keys.
 This class can iterate in both directions on the keys of a threaded tree. We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return keys instead of entries. /**
	 * An iterator on the whole range of keys.
	 *
	 * <p>
	 * This class can iterate in both directions on the keys of a threaded tree. We
	 * simply override the
	 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
	 * methods (and possibly their type-specific counterparts) so that they return
	 * keys instead of entries.
	 */
	private final class KeyIterator extends TreeIterator implements ShortListIterator {
		public KeyIterator() {
		}
		public KeyIterator(final short k) {
			super(k);
		}
		@Override
		public short nextShort() {
			return nextEntry().key;
		}
		@Override
		public short previousShort() {
			return previousEntry().key;
		}
	}
	A keyset implementation using a more direct implementation for iterators. /** A keyset implementation using a more direct implementation for iterators. */
	private class KeySet extends AbstractShort2ShortSortedMap.KeySet {
		@Override
		public ShortBidirectionalIterator iterator() {
			return new KeyIterator();
		}
		@Override
		public ShortBidirectionalIterator iterator(final short from) {
			return new KeyIterator(from);
		}
	}
	Returns a type-specific sorted set view of the keys contained in this map.
 In addition to the semantics of Map.keySet(), you can safely cast the set returned by this call to a type-specific sorted set interface. 
Returns: a type-specific sorted set view of the keys contained in this map./**
	 * Returns a type-specific sorted set view of the keys contained in this map.
	 *
	 * <p>
	 * In addition to the semantics of {@link java.util.Map#keySet()}, you can
	 * safely cast the set returned by this call to a type-specific sorted set
	 * interface.
	 *
	 * @return a type-specific sorted set view of the keys contained in this map.
	 */
	@Override
	public ShortSortedSet keySet() {
		if (keys == null)
			keys = new KeySet();
		return keys;
	}
	An iterator on the whole range of values.
 This class can iterate in both directions on the values of a threaded tree. We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return values instead of entries. /**
	 * An iterator on the whole range of values.
	 *
	 * <p>
	 * This class can iterate in both directions on the values of a threaded tree.
	 * We simply override the
	 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
	 * methods (and possibly their type-specific counterparts) so that they return
	 * values instead of entries.
	 */
	private final class ValueIterator extends TreeIterator implements ShortListIterator {
		@Override
		public short nextShort() {
			return nextEntry().value;
		}
		@Override
		public short previousShort() {
			return previousEntry().value;
		}
	}
	Returns a type-specific collection view of the values contained in this map.
 In addition to the semantics of Map.values(), you can safely cast the collection returned by this call to a type-specific collection interface. 
Returns: a type-specific collection view of the values contained in this map./**
	 * Returns a type-specific collection view of the values contained in this map.
	 *
	 * <p>
	 * In addition to the semantics of {@link java.util.Map#values()}, you can
	 * safely cast the collection returned by this call to a type-specific
	 * collection interface.
	 *
	 * @return a type-specific collection view of the values contained in this map.
	 */
	@Override
	public ShortCollection values() {
		if (values == null)
			values = new AbstractShortCollection() {
				@Override
				public ShortIterator iterator() {
					return new ValueIterator();
				}
				@Override
				public boolean contains(final short k) {
					return containsValue(k);
				}
				@Override
				public int size() {
					return count;
				}
				@Override
				public void clear() {
					Short2ShortAVLTreeMap.this.clear();
				}
			};
		return values;
	}
	@Override
	public ShortComparator comparator() {
		return actualComparator;
	}
	@Override
	public Short2ShortSortedMap headMap(short to) {
		return new Submap(((short) 0), true, to, false);
	}
	@Override
	public Short2ShortSortedMap tailMap(short from) {
		return new Submap(from, false, ((short) 0), true);
	}
	@Override
	public Short2ShortSortedMap subMap(short from, short to) {
		return new Submap(from, false, to, false);
	}
	A submap with given range.
 This class represents a submap. One has to specify the left/right limits (which can be set to -∞ or ∞). Since the submap is a view on the map, at a given moment it could happen that the limits of the range are not any longer in the main map. Thus, things such as SortedMap.firstKey() or Collection.size() must be always computed on-the-fly. /**
	 * A submap with given range.
	 *
	 * <p>
	 * This class represents a submap. One has to specify the left/right limits
	 * (which can be set to -&infin; or &infin;). Since the submap is a view on the
	 * map, at a given moment it could happen that the limits of the range are not
	 * any longer in the main map. Thus, things such as
	 * {@link java.util.SortedMap#firstKey()} or {@link java.util.Collection#size()}
	 * must be always computed on-the-fly.
	 */
	private final class Submap extends AbstractShort2ShortSortedMap implements java.io.Serializable {
		private static final long serialVersionUID = -7046029254386353129L;
		The start of the submap range, unless bottom is true. /** The start of the submap range, unless {@link #bottom} is true. */
		short from;
		The end of the submap range, unless top is true. /** The end of the submap range, unless {@link #top} is true. */
		short to;
		If true, the submap range starts from -∞. /** If true, the submap range starts from -&infin;. */
		boolean bottom;
		If true, the submap range goes to ∞. /** If true, the submap range goes to &infin;. */
		boolean top;
		Cached set of entries. /** Cached set of entries. */
		protected transient ObjectSortedSet<Short2ShortMap.Entry> entries;
		Cached set of keys. /** Cached set of keys. */
		protected transient ShortSortedSet keys;
		Cached collection of values. /** Cached collection of values. */
		protected transient ShortCollection values;
		Creates a new submap with given key range.
Params: from – 
           the start of the submap range.
bottom – 
           if true, the first parameter is ignored and the range starts from
           -∞.
to – 
           the end of the submap range.
top – 
           if true, the third parameter is ignored and the range goes to
           ∞./**
		 * Creates a new submap with given key range.
		 *
		 * @param from
		 *            the start of the submap range.
		 * @param bottom
		 *            if true, the first parameter is ignored and the range starts from
		 *            -&infin;.
		 * @param to
		 *            the end of the submap range.
		 * @param top
		 *            if true, the third parameter is ignored and the range goes to
		 *            &infin;.
		 */
		public Submap(final short from, final boolean bottom, final short to, final boolean top) {
			if (!bottom && !top && Short2ShortAVLTreeMap.this.compare(from, to) > 0)
				throw new IllegalArgumentException("Start key (" + from + ") is larger than end key (" + to + ")");
			this.from = from;
			this.bottom = bottom;
			this.to = to;
			this.top = top;
			this.defRetValue = Short2ShortAVLTreeMap.this.defRetValue;
		}
		@Override
		public void clear() {
			final SubmapIterator i = new SubmapIterator();
			while (i.hasNext()) {
				i.nextEntry();
				i.remove();
			}
		}
		Checks whether a key is in the submap range.
Params: k – 
           a key.
Returns: true if is the key is in the submap range./**
		 * Checks whether a key is in the submap range.
		 * 
		 * @param k
		 *            a key.
		 * @return true if is the key is in the submap range.
		 */
		final boolean in(final short k) {
			return (bottom || Short2ShortAVLTreeMap.this.compare(k, from) >= 0)
					&& (top || Short2ShortAVLTreeMap.this.compare(k, to) < 0);
		}
		@Override
		public ObjectSortedSet<Short2ShortMap.Entry> short2ShortEntrySet() {
			if (entries == null)
				entries = new AbstractObjectSortedSet<Short2ShortMap.Entry>() {
					@Override
					public ObjectBidirectionalIterator<Short2ShortMap.Entry> iterator() {
						return new SubmapEntryIterator();
					}
					@Override
					public ObjectBidirectionalIterator<Short2ShortMap.Entry> iterator(final Short2ShortMap.Entry from) {
						return new SubmapEntryIterator(from.getShortKey());
					}
					@Override
					public Comparator<? super Short2ShortMap.Entry> comparator() {
						return Short2ShortAVLTreeMap.this.short2ShortEntrySet().comparator();
					}
					@Override

					public boolean contains(final Object o) {
						if (!(o instanceof Map.Entry))
							return false;
						final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
						if (e.getKey() == null || !(e.getKey() instanceof Short))
							return false;
						if (e.getValue() == null || !(e.getValue() instanceof Short))
							return false;
						final Short2ShortAVLTreeMap.Entry f = findKey(((Short) (e.getKey())).shortValue());
						return f != null && in(f.key) && e.equals(f);
					}
					@Override

					public boolean remove(final Object o) {
						if (!(o instanceof Map.Entry))
							return false;
						final Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
						if (e.getKey() == null || !(e.getKey() instanceof Short))
							return false;
						if (e.getValue() == null || !(e.getValue() instanceof Short))
							return false;
						final Short2ShortAVLTreeMap.Entry f = findKey(((Short) (e.getKey())).shortValue());
						if (f != null && in(f.key))
							Submap.this.remove(f.key);
						return f != null;
					}
					@Override
					public int size() {
						int c = 0;
						for (Iterator<?> i = iterator(); i.hasNext(); i.next())
							c++;
						return c;
					}
					@Override
					public boolean isEmpty() {
						return !new SubmapIterator().hasNext();
					}
					@Override
					public void clear() {
						Submap.this.clear();
					}
					@Override
					public Short2ShortMap.Entry first() {
						return firstEntry();
					}
					@Override
					public Short2ShortMap.Entry last() {
						return lastEntry();
					}
					@Override
					public ObjectSortedSet<Short2ShortMap.Entry> subSet(Short2ShortMap.Entry from,
							Short2ShortMap.Entry to) {
						return subMap(from.getShortKey(), to.getShortKey()).short2ShortEntrySet();
					}
					@Override
					public ObjectSortedSet<Short2ShortMap.Entry> headSet(Short2ShortMap.Entry to) {
						return headMap(to.getShortKey()).short2ShortEntrySet();
					}
					@Override
					public ObjectSortedSet<Short2ShortMap.Entry> tailSet(Short2ShortMap.Entry from) {
						return tailMap(from.getShortKey()).short2ShortEntrySet();
					}
				};
			return entries;
		}
		private class KeySet extends AbstractShort2ShortSortedMap.KeySet {
			@Override
			public ShortBidirectionalIterator iterator() {
				return new SubmapKeyIterator();
			}
			@Override
			public ShortBidirectionalIterator iterator(final short from) {
				return new SubmapKeyIterator(from);
			}
		}
		@Override
		public ShortSortedSet keySet() {
			if (keys == null)
				keys = new KeySet();
			return keys;
		}
		@Override
		public ShortCollection values() {
			if (values == null)
				values = new AbstractShortCollection() {
					@Override
					public ShortIterator iterator() {
						return new SubmapValueIterator();
					}
					@Override
					public boolean contains(final short k) {
						return containsValue(k);
					}
					@Override
					public int size() {
						return Submap.this.size();
					}
					@Override
					public void clear() {
						Submap.this.clear();
					}
				};
			return values;
		}
		@Override

		public boolean containsKey(final short k) {
			return in(k) && Short2ShortAVLTreeMap.this.containsKey(k);
		}
		@Override
		public boolean containsValue(final short v) {
			final SubmapIterator i = new SubmapIterator();
			short ev;
			while (i.hasNext()) {
				ev = i.nextEntry().value;
				if (((ev) == (v)))
					return true;
			}
			return false;
		}
		@Override

		public short get(final short k) {
			final Short2ShortAVLTreeMap.Entry e;
			final short kk = k;
			return in(kk) && (e = findKey(kk)) != null ? e.value : this.defRetValue;
		}
		@Override
		public short put(final short k, final short v) {
			modified = false;
			if (!in(k))
				throw new IllegalArgumentException("Key (" + k + ") out of range ["
						+ (bottom ? "-" : String.valueOf(from)) + ", " + (top ? "-" : String.valueOf(to)) + ")");
			final short oldValue = Short2ShortAVLTreeMap.this.put(k, v);
			return modified ? this.defRetValue : oldValue;
		}
		@Override

		public short remove(final short k) {
			modified = false;
			if (!in(k))
				return this.defRetValue;
			final short oldValue = Short2ShortAVLTreeMap.this.remove(k);
			return modified ? oldValue : this.defRetValue;
		}
		@Override
		public int size() {
			final SubmapIterator i = new SubmapIterator();
			int n = 0;
			while (i.hasNext()) {
				n++;
				i.nextEntry();
			}
			return n;
		}
		@Override
		public boolean isEmpty() {
			return !new SubmapIterator().hasNext();
		}
		@Override
		public ShortComparator comparator() {
			return actualComparator;
		}
		@Override
		public Short2ShortSortedMap headMap(final short to) {
			if (top)
				return new Submap(from, bottom, to, false);
			return compare(to, this.to) < 0 ? new Submap(from, bottom, to, false) : this;
		}
		@Override
		public Short2ShortSortedMap tailMap(final short from) {
			if (bottom)
				return new Submap(from, false, to, top);
			return compare(from, this.from) > 0 ? new Submap(from, false, to, top) : this;
		}
		@Override
		public Short2ShortSortedMap subMap(short from, short to) {
			if (top && bottom)
				return new Submap(from, false, to, false);
			if (!top)
				to = compare(to, this.to) < 0 ? to : this.to;
			if (!bottom)
				from = compare(from, this.from) > 0 ? from : this.from;
			if (!top && !bottom && from == this.from && to == this.to)
				return this;
			return new Submap(from, false, to, false);
		}
		Locates the first entry.
Returns: the first entry of this submap, or null if the submap is empty./**
		 * Locates the first entry.
		 *
		 * @return the first entry of this submap, or {@code null} if the submap is
		 *         empty.
		 */
		public Short2ShortAVLTreeMap.Entry firstEntry() {
			if (tree == null)
				return null;
			// If this submap goes to -infinity, we return the main map first entry;
			// otherwise, we locate the start of the map.
			Short2ShortAVLTreeMap.Entry e;
			if (bottom)
				e = firstEntry;
			else {
				e = locateKey(from);
				// If we find either the start or something greater we're OK.
				if (compare(e.key, from) < 0)
					e = e.next();
			}
			// Finally, if this subset doesn't go to infinity, we check that the resulting
			// key isn't greater than the end.
			if (e == null || !top && compare(e.key, to) >= 0)
				return null;
			return e;
		}
		Locates the last entry.
Returns: the last entry of this submap, or null if the submap is empty./**
		 * Locates the last entry.
		 *
		 * @return the last entry of this submap, or {@code null} if the submap is
		 *         empty.
		 */
		public Short2ShortAVLTreeMap.Entry lastEntry() {
			if (tree == null)
				return null;
			// If this submap goes to infinity, we return the main map last entry;
			// otherwise, we locate the end of the map.
			Short2ShortAVLTreeMap.Entry e;
			if (top)
				e = lastEntry;
			else {
				e = locateKey(to);
				// If we find something smaller than the end we're OK.
				if (compare(e.key, to) >= 0)
					e = e.prev();
			}
			// Finally, if this subset doesn't go to -infinity, we check that the resulting
			// key isn't smaller than the start.
			if (e == null || !bottom && compare(e.key, from) < 0)
				return null;
			return e;
		}
		@Override
		public short firstShortKey() {
			Short2ShortAVLTreeMap.Entry e = firstEntry();
			if (e == null)
				throw new NoSuchElementException();
			return e.key;
		}
		@Override
		public short lastShortKey() {
			Short2ShortAVLTreeMap.Entry e = lastEntry();
			if (e == null)
				throw new NoSuchElementException();
			return e.key;
		}
		An iterator for subranges.
 This class inherits from TreeIterator, but overrides the methods that update the pointer after a ListIterator.next() or ListIterator.previous(). If we would move out of the range of the submap we just overwrite the next or previous entry with null. /**
		 * An iterator for subranges.
		 *
		 * <p>
		 * This class inherits from {@link TreeIterator}, but overrides the methods that
		 * update the pointer after a {@link java.util.ListIterator#next()} or
		 * {@link java.util.ListIterator#previous()}. If we would move out of the range
		 * of the submap we just overwrite the next or previous entry with {@code null}.
		 */
		private class SubmapIterator extends TreeIterator {
			SubmapIterator() {
				next = firstEntry();
			}
			SubmapIterator(final short k) {
				this();
				if (next != null) {
					if (!bottom && compare(k, next.key) < 0)
						prev = null;
					else if (!top && compare(k, (prev = lastEntry()).key) >= 0)
						next = null;
					else {
						next = locateKey(k);
						if (compare(next.key, k) <= 0) {
							prev = next;
							next = next.next();
						} else
							prev = next.prev();
					}
				}
			}
			@Override
			void updatePrevious() {
				prev = prev.prev();
				if (!bottom && prev != null && Short2ShortAVLTreeMap.this.compare(prev.key, from) < 0)
					prev = null;
			}
			@Override
			void updateNext() {
				next = next.next();
				if (!top && next != null && Short2ShortAVLTreeMap.this.compare(next.key, to) >= 0)
					next = null;
			}
		}
		private class SubmapEntryIterator extends SubmapIterator implements ObjectListIterator<Short2ShortMap.Entry> {
			SubmapEntryIterator() {
			}
			SubmapEntryIterator(final short k) {
				super(k);
			}
			@Override
			public Short2ShortMap.Entry next() {
				return nextEntry();
			}
			@Override
			public Short2ShortMap.Entry previous() {
				return previousEntry();
			}
		}
		An iterator on a subrange of keys.
 This class can iterate in both directions on a subrange of the keys of a threaded tree. We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return keys instead of entries. /**
		 * An iterator on a subrange of keys.
		 *
		 * <p>
		 * This class can iterate in both directions on a subrange of the keys of a
		 * threaded tree. We simply override the
		 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
		 * methods (and possibly their type-specific counterparts) so that they return
		 * keys instead of entries.
		 */
		private final class SubmapKeyIterator extends SubmapIterator implements ShortListIterator {
			public SubmapKeyIterator() {
				super();
			}
			public SubmapKeyIterator(short from) {
				super(from);
			}
			@Override
			public short nextShort() {
				return nextEntry().key;
			}
			@Override
			public short previousShort() {
				return previousEntry().key;
			}
		};
		An iterator on a subrange of values.
 This class can iterate in both directions on the values of a subrange of the keys of a threaded tree. We simply override the ListIterator.next()/ListIterator.previous() methods (and possibly their type-specific counterparts) so that they return values instead of entries. /**
		 * An iterator on a subrange of values.
		 *
		 * <p>
		 * This class can iterate in both directions on the values of a subrange of the
		 * keys of a threaded tree. We simply override the
		 * {@link java.util.ListIterator#next()}/{@link java.util.ListIterator#previous()}
		 * methods (and possibly their type-specific counterparts) so that they return
		 * values instead of entries.
		 */
		private final class SubmapValueIterator extends SubmapIterator implements ShortListIterator {
			@Override
			public short nextShort() {
				return nextEntry().value;
			}
			@Override
			public short previousShort() {
				return previousEntry().value;
			}
		};
	}
	Returns a deep copy of this tree map.

This method performs a deep copy of this tree map; the data stored in the
set, however, is not cloned. Note that this makes a difference only for
object keys.
Returns: a deep copy of this tree map./**
	 * Returns a deep copy of this tree map.
	 *
	 * <p>
	 * This method performs a deep copy of this tree map; the data stored in the
	 * set, however, is not cloned. Note that this makes a difference only for
	 * object keys.
	 *
	 * @return a deep copy of this tree map.
	 */
	@Override

	public Short2ShortAVLTreeMap clone() {
		Short2ShortAVLTreeMap c;
		try {
			c = (Short2ShortAVLTreeMap) super.clone();
		} catch (CloneNotSupportedException cantHappen) {
			throw new InternalError();
		}
		c.keys = null;
		c.values = null;
		c.entries = null;
		c.allocatePaths();
		if (count != 0) {
			// Also this apparently unfathomable code is derived from GNU libavl.
			Entry e, p, q, rp = new Entry(), rq = new Entry();
			p = rp;
			rp.left(tree);
			q = rq;
			rq.pred(null);
			while (true) {
				if (!p.pred()) {
					e = p.left.clone();
					e.pred(q.left);
					e.succ(q);
					q.left(e);
					p = p.left;
					q = q.left;
				} else {
					while (p.succ()) {
						p = p.right;
						if (p == null) {
							q.right = null;
							c.tree = rq.left;
							c.firstEntry = c.tree;
							while (c.firstEntry.left != null)
								c.firstEntry = c.firstEntry.left;
							c.lastEntry = c.tree;
							while (c.lastEntry.right != null)
								c.lastEntry = c.lastEntry.right;
							return c;
						}
						q = q.right;
					}
					p = p.right;
					q = q.right;
				}
				if (!p.succ()) {
					e = p.right.clone();
					e.succ(q.right);
					e.pred(q);
					q.right(e);
				}
			}
		}
		return c;
	}
	private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
		int n = count;
		EntryIterator i = new EntryIterator();
		Entry e;
		s.defaultWriteObject();
		while (n-- != 0) {
			e = i.nextEntry();
			s.writeShort(e.key);
			s.writeShort(e.value);
		}
	}
	Reads the given number of entries from the input stream, returning the
corresponding tree.
Params: s – 
           the input stream.
n – 
           the (positive) number of entries to read.
pred – 
           the entry containing the key that preceeds the first key in the
           tree.
succ – 
           the entry containing the key that follows the last key in the
           tree./**
	 * Reads the given number of entries from the input stream, returning the
	 * corresponding tree.
	 *
	 * @param s
	 *            the input stream.
	 * @param n
	 *            the (positive) number of entries to read.
	 * @param pred
	 *            the entry containing the key that preceeds the first key in the
	 *            tree.
	 * @param succ
	 *            the entry containing the key that follows the last key in the
	 *            tree.
	 */

	private Entry readTree(final java.io.ObjectInputStream s, final int n, final Entry pred, final Entry succ)
			throws java.io.IOException, ClassNotFoundException {
		if (n == 1) {
			final Entry top = new Entry(s.readShort(), s.readShort());
			top.pred(pred);
			top.succ(succ);
			return top;
		}
		if (n == 2) {
			/*
			 * We handle separately this case so that recursion will always* be on nonempty
			 * subtrees.
			 */
			final Entry top = new Entry(s.readShort(), s.readShort());
			top.right(new Entry(s.readShort(), s.readShort()));
			top.right.pred(top);
			top.balance(1);
			top.pred(pred);
			top.right.succ(succ);
			return top;
		}
		// The right subtree is the largest one.
		final int rightN = n / 2, leftN = n - rightN - 1;
		final Entry top = new Entry();
		top.left(readTree(s, leftN, pred, top));
		top.key = s.readShort();
		top.value = s.readShort();
		top.right(readTree(s, rightN, top, succ));
		if (n == (n & -n))
			top.balance(1); // Quick test for determining whether n is a power of 2.
		return top;
	}
	private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();
		/*
		 * The storedComparator is now correctly set, but we must restore on-the-fly the
		 * actualComparator.
		 */
		setActualComparator();
		allocatePaths();
		if (count != 0) {
			tree = readTree(s, count, null, null);
			Entry e;
			e = tree;
			while (e.left() != null)
				e = e.left();
			firstEntry = e;
			e = tree;
			while (e.right() != null)
				e = e.right();
			lastEntry = e;
		}
	}
}
Params:	k – the array of keys of the new tree map. v – the array of corresponding values in the new tree map. c – a (possibly type-specific) comparator.
Throws:	IllegalArgumentException – if `k` and `v` have different lengths.
Params:	k1 – the first key. k2 – the second key.
Returns:	a number smaller than, equal to or greater than 0, as usual (i.e., when k1 < k2, k1 = k2 or k1 > k2, respectively).
Params:	k – the key to search for.
Returns:	the corresponding entry, or `null` if no entry with the given key exists.
Params:	k – a key.
Returns:	the last entry on a search for the given key; this will be the given key, if it present; otherwise, it will be either the smallest greater key or the greatest smaller key.
Params:	k – the key. incr – the increment.
Returns:	the old value, or the default return value if no value was present for the given key.
Params:	k – the key
Returns:	a node with key k. If a node with key k already exists, then that node is returned, otherwise a new node with defRetValue is created ensuring that the tree is balanced after creation of the node.
Params:	e – a node of the tree.
Returns:	the parent of the given node, or `null` for the root.
/

it.unimi.dsi/ fastutil/ 8.3.0/ it/unimi/dsi/fastutil/shorts/Short2ShortAVLTreeMap.java
