treeMap 也是使用红黑树实现的
package com.numberone.tree;
/**
* 红黑树
*/
public class RBTree<T extends Comparable<T>> {
private final RBTreeNode<T> root;
//node number
private java.util.concurrent.atomic.AtomicLong size =
new java.util.concurrent.atomic.AtomicLong(0);
//in overwrite mode,all node's value can not has same value
//in non-overwrite mode,node can have same value, suggest don't use non-overwrite mode.
private volatile boolean overrideMode = true;
public RBTree() {
this.root = new RBTreeNode<T>();
}
public RBTree(boolean overrideMode) {
this();
this.overrideMode = overrideMode;
}
public boolean isOverrideMode() {
return overrideMode;
}
public void setOverrideMode(boolean overrideMode) {
this.overrideMode = overrideMode;
}
/**
* number of tree number
*
* @return
*/
public long getSize() {
return size.get();
}
/**
* get the root node
*
* @return
*/
private RBTreeNode<T> getRoot() {
return root.getLeft();
}
/**
* add value to a new node,if this value exist in this tree,
* if value exist,it will return the exist value.otherwise return null
* if override mode is true,if value exist in the tree,
* it will override the old value in the tree
* @param value
* @return
*/
public T addNode(T value) {
RBTreeNode<T> t = new RBTreeNode<T>(value);
return addNode(t);
}
/**
* find the value by give value(include key,key used for search,
* other field is not used,@see compare method).if this value not exist return null
*
* @param value
* @return
*/
public T find(T value) {
RBTreeNode<T> dataRoot = getRoot();
while (dataRoot != null) {
int cmp = dataRoot.getValue().compareTo(value);
if (cmp < 0) {
dataRoot = dataRoot.getRight();
} else if (cmp > 0) {
dataRoot = dataRoot.getLeft();
} else {
return dataRoot.getValue();
}
}
return null;
}
/**
* remove the node by give value,if this value not exists in tree return null
*
* @param value include search key
* @return the value contain in the removed node
*/
public T remove(T value) {
RBTreeNode<T> dataRoot = getRoot();
RBTreeNode<T> parent = root;
while (dataRoot != null) {
int cmp = dataRoot.getValue().compareTo(value);
if (cmp < 0) {
parent = dataRoot;
dataRoot = dataRoot.getRight();
} else if (cmp > 0) {
parent = dataRoot;
dataRoot = dataRoot.getLeft();
} else {
if (dataRoot.getRight() != null) {
RBTreeNode<T> min = removeMin(dataRoot.getRight());
//x used for fix color balance
RBTreeNode<T> x = min.getRight() == null ? min.getParent() : min.getRight();
boolean isParent = min.getRight() == null;
min.setLeft(dataRoot.getLeft());
setParent(dataRoot.getLeft(), min);
if (parent.getLeft() == dataRoot) {
parent.setLeft(min);
} else {
parent.setRight(min);
}
setParent(min, parent);
boolean curMinIsBlack = min.isBlack();
//inherit dataRoot's color
min.setRed(dataRoot.isRed());
if (min != dataRoot.getRight()) {
min.setRight(dataRoot.getRight());
setParent(dataRoot.getRight(), min);
}
//remove a black node,need fix color
if (curMinIsBlack) {
if (min != dataRoot.getRight()) {
fixRemove(x, isParent);
} else if (min.getRight() != null) {
fixRemove(min.getRight(), false);
} else {
fixRemove(min, true);
}
}
} else {
setParent(dataRoot.getLeft(), parent);
if (parent.getLeft() == dataRoot) {
parent.setLeft(dataRoot.getLeft());
} else {
parent.setRight(dataRoot.getLeft());
}
//current node is black and tree is not empty
if (dataRoot.isBlack() && !(root.getLeft() == null)) {
RBTreeNode<T> x = dataRoot.getLeft() == null
? parent : dataRoot.getLeft();
boolean isParent = dataRoot.getLeft() == null;
fixRemove(x, isParent);
}
}
setParent(dataRoot, null);
dataRoot.setLeft(null);
dataRoot.setRight(null);
if (getRoot() != null) {
getRoot().setRed(false);
getRoot().setParent(null);
}
size.decrementAndGet();
return dataRoot.getValue();
}
}
return null;
}
/**
* fix remove action
*
* @param node
* @param isParent
*/
private void fixRemove(RBTreeNode<T> node, boolean isParent) {
RBTreeNode<T> cur = isParent ? null : node;
boolean isRed = isParent ? false : node.isRed();
RBTreeNode<T> parent = isParent ? node : node.getParent();
while (!isRed && !isRoot(cur)) {
RBTreeNode<T> sibling = getSibling(cur, parent);
//sibling is not null,due to before remove tree color is balance
//if cur is a left node
boolean isLeft = parent.getRight() == sibling;
if (sibling.isRed() && !isLeft) {//case 1
//cur in right
parent.makeRed();
sibling.makeBlack();
rotateRight(parent);
} else if (sibling.isRed() && isLeft) {
//cur in left
parent.makeRed();
sibling.makeBlack();
rotateLeft(parent);
} else if (isBlack(sibling.getLeft()) && isBlack(sibling.getRight())) {//case 2
sibling.makeRed();
cur = parent;
isRed = cur.isRed();
parent = parent.getParent();
} else if (isLeft && !isBlack(sibling.getLeft())
&& isBlack(sibling.getRight())) {//case 3
sibling.makeRed();
sibling.getLeft().makeBlack();
rotateRight(sibling);
} else if (!isLeft && !isBlack(sibling.getRight())
&& isBlack(sibling.getLeft())) {
sibling.makeRed();
sibling.getRight().makeBlack();
rotateLeft(sibling);
} else if (isLeft && !isBlack(sibling.getRight())) {//case 4
sibling.setRed(parent.isRed());
parent.makeBlack();
sibling.getRight().makeBlack();
rotateLeft(parent);
cur = getRoot();
} else if (!isLeft && !isBlack(sibling.getLeft())) {
sibling.setRed(parent.isRed());
parent.makeBlack();
sibling.getLeft().makeBlack();
rotateRight(parent);
cur = getRoot();
}
}
if (isRed) {
cur.makeBlack();
}
if (getRoot() != null) {
getRoot().setRed(false);
getRoot().setParent(null);
}
}
//get sibling node
private RBTreeNode<T> getSibling(RBTreeNode<T> node, RBTreeNode<T> parent) {
parent = node == null ? parent : node.getParent();
if (node == null) {
return parent.getLeft() == null ? parent.getRight() : parent.getLeft();
}
if (node == parent.getLeft()) {
return parent.getRight();
} else {
return parent.getLeft();
}
}
private boolean isBlack(RBTreeNode<T> node) {
return node == null || node.isBlack();
}
private boolean isRoot(RBTreeNode<T> node) {
return root.getLeft() == node && node.getParent() == null;
}
/**
* find the successor node
*
* @param node current node's right node
* @return
*/
private RBTreeNode<T> removeMin(RBTreeNode<T> node) {
//find the min node
RBTreeNode<T> parent = node;
while (node != null && node.getLeft() != null) {
parent = node;
node = node.getLeft();
}
//remove min node
if (parent == node) {
return node;
}
parent.setLeft(node.getRight());
setParent(node.getRight(), parent);
//don't remove right pointer,it is used for fixed color balance
//node.setRight(null);
return node;
}
private T addNode(RBTreeNode<T> node) {
node.setLeft(null);
node.setRight(null);
node.setRed(true);
setParent(node, null);
if (root.getLeft() == null) {
root.setLeft(node);
//root node is black
node.setRed(false);
size.incrementAndGet();
} else {
RBTreeNode<T> x = findParentNode(node);
int cmp = x.getValue().compareTo(node.getValue());
if (this.overrideMode && cmp == 0) {
T v = x.getValue();
x.setValue(node.getValue());
return v;
} else if (cmp == 0) {
//value exists,ignore this node
return x.getValue();
}
setParent(node, x);
if (cmp > 0) {
x.setLeft(node);
} else {
x.setRight(node);
}
fixInsert(node);
size.incrementAndGet();
}
return null;
}
/**
* find the parent node to hold node x,if parent value equals x.value return parent.
*
* @param x
* @return
*/
private RBTreeNode<T> findParentNode(RBTreeNode<T> x) {
RBTreeNode<T> dataRoot = getRoot();
RBTreeNode<T> child = dataRoot;
while (child != null) {
int cmp = child.getValue().compareTo(x.getValue());
if (cmp == 0) {
return child;
}
if (cmp > 0) {
dataRoot = child;
child = child.getLeft();
} else if (cmp < 0) {
dataRoot = child;
child = child.getRight();
}
}
return dataRoot;
}
/**
* red black tree insert fix.
*
* @param x
*/
private void fixInsert(RBTreeNode<T> x) {
RBTreeNode<T> parent = x.getParent();
while (parent != null && parent.isRed()) {
RBTreeNode<T> uncle = getUncle(x);
if (uncle == null) {//need to rotate
RBTreeNode<T> ancestor = parent.getParent();
//ancestor is not null due to before before add,tree color is balance
if (parent == ancestor.getLeft()) {
boolean isRight = x == parent.getRight();
if (isRight) {
rotateLeft(parent);
}
rotateRight(ancestor);
if (isRight) {
x.setRed(false);
parent = null;//end loop
} else {
parent.setRed(false);
}
ancestor.setRed(true);
} else {
boolean isLeft = x == parent.getLeft();
if (isLeft) {
rotateRight(parent);
}
rotateLeft(ancestor);
if (isLeft) {
x.setRed(false);
parent = null;//end loop
} else {
parent.setRed(false);
}
ancestor.setRed(true);
}
} else {//uncle is red
parent.setRed(false);
uncle.setRed(false);
parent.getParent().setRed(true);
x = parent.getParent();
parent = x.getParent();
}
}
getRoot().makeBlack();
getRoot().setParent(null);
}
/**
* get uncle node
*
* @param node
* @return
*/
private RBTreeNode<T> getUncle(RBTreeNode<T> node) {
RBTreeNode<T> parent = node.getParent();
RBTreeNode<T> ancestor = parent.getParent();
if (ancestor == null) {
return null;
}
if (parent == ancestor.getLeft()) {
return ancestor.getRight();
} else {
return ancestor.getLeft();
}
}
private void rotateLeft(RBTreeNode<T> node) {
RBTreeNode<T> right = node.getRight();
if (right == null) {
throw new IllegalStateException("right node is null");
}
RBTreeNode<T> parent = node.getParent();
node.setRight(right.getLeft());
setParent(right.getLeft(), node);
right.setLeft(node);
setParent(node, right);
if (parent == null) {//node pointer to root
//right raise to root node
root.setLeft(right);
setParent(right, null);
} else {
if (parent.getLeft() == node) {
parent.setLeft(right);
} else {
parent.setRight(right);
}
//right.setParent(parent);
setParent(right, parent);
}
}
private void rotateRight(RBTreeNode<T> node) {
RBTreeNode<T> left = node.getLeft();
if (left == null) {
throw new IllegalStateException("left node is null");
}
RBTreeNode<T> parent = node.getParent();
node.setLeft(left.getRight());
setParent(left.getRight(), node);
left.setRight(node);
setParent(node, left);
if (parent == null) {
root.setLeft(left);
setParent(left, null);
} else {
if (parent.getLeft() == node) {
parent.setLeft(left);
} else {
parent.setRight(left);
}
setParent(left, parent);
}
}
private void setParent(RBTreeNode<T> node, RBTreeNode<T> parent) {
if (node != null) {
node.setParent(parent);
if (parent == root) {
node.setParent(null);
}
}
}
/**
* debug method,it used print the given node and its children nodes,
* every layer output in one line
*
* @param root
*/
public void printTree(RBTreeNode<T> root) {
java.util.LinkedList<RBTreeNode<T>> queue = new java.util.LinkedList<RBTreeNode<T>>();
java.util.LinkedList<RBTreeNode<T>> queue2 = new java.util.LinkedList<RBTreeNode<T>>();
if (root == null) {
return;
}
queue.add(root);
boolean firstQueue = true;
while (!queue.isEmpty() || !queue2.isEmpty()) {
java.util.LinkedList<RBTreeNode<T>> q = firstQueue ? queue : queue2;
RBTreeNode<T> n = q.poll();
if (n != null) {
String pos = n.getParent() == null ? "" : (n == n.getParent().getLeft()
? " LE" : " RI");
String pstr = n.getParent() == null ? "" : n.getParent().toString();
String cstr = n.isRed() ? "R" : "B";
cstr = n.getParent() == null ? cstr : cstr + " ";
System.out.print(n + "(" + (cstr) + pstr + (pos) + ")" + "\t");
if (n.getLeft() != null) {
(firstQueue ? queue2 : queue).add(n.getLeft());
}
if (n.getRight() != null) {
(firstQueue ? queue2 : queue).add(n.getRight());
}
} else {
System.out.println();
firstQueue = !firstQueue;
}
}
}
}
package com.numberone.tree;
/**
* Created on 2020/1/7.
*
* 红黑树实体类
* @author Gray
* @since 1.0
*/
public class RBTreeNode<T extends Comparable<T>> {
private T value;
private RBTreeNode<T> left;
private RBTreeNode<T> right;
private RBTreeNode<T> parent;
private boolean red;//color is red or not red
public RBTreeNode(){}
public RBTreeNode(T value){this.value=value;}
public RBTreeNode(T value,boolean isRed){this.value=value;this.red = isRed;}
public T getValue() {
return value;
}
void setValue(T value) {
this.value = value;
}
RBTreeNode<T> getLeft() {
return left;
}
void setLeft(RBTreeNode<T> left) {
this.left = left;
}
RBTreeNode<T> getRight() {
return right;
}
void setRight(RBTreeNode<T> right) {
this.right = right;
}
RBTreeNode<T> getParent() {
return parent;
}
void setParent(RBTreeNode<T> parent) {
this.parent = parent;
}
boolean isRed() {
return red;
}
boolean isBlack(){
return !red;
}
/**
* is leaf node
**/
boolean isLeaf(){
return left==null && right==null;
}
void setRed(boolean red) {
this.red = red;
}
void makeRed(){
red=true;
}
void makeBlack(){
red=false;
}
@Override
public String toString(){
return value.toString();
}
}
