1、源码：
package demo20;
/**
* @description implementation of Red-Black Tree by Java
* @author eson_15
* @param <T>
* @date 2016-4-18 19:27:28
*/
public class RBTree<T extends Comparable<T>> {
private RBNode<T> root; //根节点
private static final boolean RED = false; //定义红黑树标志
private static final boolean BLACK = true;
//内部类：节点类
public class RBNode<T extends Comparable<T>>{
boolean color; //颜色
T key; //关键字(键值)
RBNode<T> left; //左子节点
RBNode<T> right; //右子节点
RBNode<T> parent; //父节点
public RBNode(T key, boolean color, RBNode<T> parent, RBNode<T> left, RBNode<T> right) {
this.key = key;
this.color = color;
this.parent = parent;
this.left = left;
this.right = right;
}
public T getKey() {
return key;
}
public String toString() {
return "" + key + (this.color == RED? "R" : "B");
}
}
public RBTree() {
root = null;
}
public RBNode<T> parentOf(RBNode<T> node) { //获得父节点
return node != null? node.parent : null;
}
public void setParent(RBNode<T> node, RBNode<T> parent) { //设置父节点
if(node != null)
node.parent = parent;
}
public boolean colorOf(RBNode<T> node) { //获得节点的颜色
return node != null? node.color : BLACK;
}
public boolean isRed(RBNode<T> node) { //判断节点的颜色
return (node != null)&&(node.color == RED)? true : false;
}
public boolean isBlack(RBNode<T> node) {
return !isRed(node);
}
public void setRed(RBNode<T> node) { //设置节点的颜色
if(node != null)
node.color = RED;
}
public void setBlack(RBNode<T> node) {
if(node != null) {
node.color = BLACK;
}
}
public void setColor(RBNode<T> node, boolean color) {
if(node != null)
node.color = color;
}
/***************** 前序遍历红黑树 *********************/
public void preOrder() {
preOrder(root);
}
private void preOrder(RBNode<T> tree) {
if(tree != null) {
System.out.print(tree.key + " ");
preOrder(tree.left);
preOrder(tree.right);
}
}
/***************** 中序遍历红黑树 *********************/
public void inOrder() {
inOrder(root);
}
private void inOrder(RBNode<T> tree) {
if(tree != null) {
preOrder(tree.left);
System.out.print(tree.key + " ");
preOrder(tree.right);
}
}
/***************** 后序遍历红黑树 *********************/
public void postOrder() {
postOrder(root);
}
private void postOrder(RBNode<T> tree) {
if(tree != null) {
preOrder(tree.left);
preOrder(tree.right);
System.out.print(tree.key + " ");
}
}
/**************** 查找红黑树中键值为key的节点 ***************/
public RBNode<T> search(T key) {
return search(root, key);
// return search2(root, key); //使用递归的方法，本质一样的
}
private RBNode<T> search(RBNode<T> x, T key) {
while(x != null) {
int cmp = key.compareTo(x.key);
if(cmp < 0)
x = x.left;
else if(cmp > 0)
x = x.right;
else
return x;
}
return x;
}
//使用递归
private RBNode<T> search2(RBNode<T> x, T key) {
if(x == null)
return x;
int cmp = key.compareTo(x.key);
if(cmp < 0)
return search2(x.left, key);
else if(cmp > 0)
return search2(x.right, key);
else
return x;
}
/**************** 查找最小节点的值 **********************/
public T minValue() {
RBNode<T> node = minNode(root);
if(node != null)
return node.key;
return null;
}
private RBNode<T> minNode(RBNode<T> tree) {
if(tree == null)
return null;
while(tree.left != null) {
tree = tree.left;
}
return tree;
}
/******************** 查找最大节点的值 *******************/
public T maxValue() {
RBNode<T> node = maxNode(root);
if(node != null)
return node.key;
return null;
}
private RBNode<T> maxNode(RBNode<T> tree) {
if(tree == null)
return null;
while(tree.right != null)
tree = tree.right;
return tree;
}
/********* 查找节点x的后继节点,即大于节点x的最小节点 ***********/
public RBNode<T> successor(RBNode<T> x) {
//如果x有右子节点，那么后继节点为“以右子节点为根的子树的最小节点”
if(x.right != null)
return minNode(x.right);
//如果x没有右子节点，会出现以下两种情况：
//1. x是其父节点的左子节点，则x的后继节点为它的父节点
//2. x是其父节点的右子节点，则先查找x的父节点p，然后对p再次进行这两个条件的判断
RBNode<T> p = x.parent;
while((p != null) && (x == p.right)) { //对应情况2
x = p;
p = x.parent;
}
return p; //对应情况1
}
/********* 查找节点x的前驱节点，即小于节点x的最大节点 ************/
public RBNode<T> predecessor(RBNode<T> x) {
//如果x有左子节点，那么前驱结点为“左子节点为根的子树的最大节点”
if(x.left != null)
return maxNode(x.left);
//如果x没有左子节点，会出现以下两种情况：
//1. x是其父节点的右子节点，则x的前驱节点是它的父节点
//2. x是其父节点的左子节点，则先查找x的父节点p，然后对p再次进行这两个条件的判断
RBNode<T> p = x.parent;
while((p != null) && (x == p.left)) { //对应情况2
x = p;
p = x.parent;
}
return p; //对应情况1
}
/*************对红黑树节点x进行左旋操作 ******************/
/*
* 左旋示意图：对节点x进行左旋
* p p
* / /
* x y
* / \ / \
* lx y -----> x ry
* / \ / \
* ly ry lx ly
* 左旋做了三件事：
* 1. 将y的左子节点赋给x的右子节点,并将x赋给y左子节点的父节点(y左子节点非空时)
* 2. 将x的父节点p(非空时)赋给y的父节点，同时更新p的子节点为y(左或右)
* 3. 将y的左子节点设为x，将x的父节点设为y
*/
private void leftRotate(RBNode<T> x) {
//1. 将y的左子节点赋给x的右子节点，并将x赋给y左子节点的父节点(y左子节点非空时)
RBNode<T> y = x.right;
x.right = y.left;
if(y.left != null)
y.left.parent = x;
//2. 将x的父节点p(非空时)赋给y的父节点，同时更新p的子节点为y(左或右)
y.parent = x.parent;
if(x.parent == null) {
this.root = y; //如果x的父节点为空，则将y设为父节点
} else {
if(x == x.parent.left) //如果x是左子节点
x.parent.left = y; //则也将y设为左子节点
else
x.parent.right = y;//否则将y设为右子节点
}
//3. 将y的左子节点设为x，将x的父节点设为y
y.left = x;
x.parent = y;
}
/*************对红黑树节点y进行右旋操作 ******************/
/*
* 左旋示意图：对节点y进行右旋
* p p
* / /
* y x
* / \ / \
* x ry -----> lx y
* / \ / \
* lx rx rx ry
* 右旋做了三件事：
* 1. 将x的右子节点赋给y的左子节点,并将y赋给x右子节点的父节点(x右子节点非空时)
* 2. 将y的父节点p(非空时)赋给x的父节点，同时更新p的子节点为x(左或右)
* 3. 将x的右子节点设为y，将y的父节点设为x
*/
private void rightRotate(RBNode<T> y) {
//1. 将y的左子节点赋给x的右子节点，并将x赋给y左子节点的父节点(y左子节点非空时)
RBNode<T> x = y.left;
y.left = x.right;
if(x.right != null)
x.right.parent = y;
//2. 将x的父节点p(非空时)赋给y的父节点，同时更新p的子节点为y(左或右)
x.parent = y.parent;
if(y.parent == null) {
this.root = x; //如果x的父节点为空，则将y设为父节点
} else {
if(y == y.parent.right) //如果x是左子节点
y.parent.right = x; //则也将y设为左子节点
else
y.parent.left = x;//否则将y设为右子节点
}
//3. 将y的左子节点设为x，将x的父节点设为y
x.right = y;
y.parent = x;
}
/*********************** 向红黑树中插入节点 **********************/
public void insert(T key) {
RBNode<T> node = new RBNode<T>(key, RED, null, null, null);
if(node != null)
insert(node);
}
//将节点插入到红黑树中，这个过程与二叉搜索树是一样的
private void insert(RBNode<T> node) {
RBNode<T> current = null; //表示最后node的父节点
RBNode<T> x = this.root; //用来向下搜索用的
//1. 找到插入的位置
while(x != null) {
current = x;
int cmp = node.key.compareTo(x.key);
if(cmp < 0)
x = x.left;
else
x = x.right;
}
node.parent = current; //找到了位置，将当前current作为node的父节点
//2. 接下来判断node是插在左子节点还是右子节点
if(current != null) {
int cmp = node.key.compareTo(current.key);
if(cmp < 0)
current.left = node;
else
current.right = node;
} else {
this.root = node;
}
//3. 将它重新修整为一颗红黑树
insertFixUp(node);
}
private void insertFixUp(RBNode<T> node) {
RBNode<T> parent, gparent; //定义父节点和祖父节点
//需要修整的条件：父节点存在，且父节点的颜色是红色
while(((parent = parentOf(node)) != null) && isRed(parent)) {
gparent = parentOf(parent);//获得祖父节点
//若父节点是祖父节点的左子节点，下面else与其相反
if(parent == gparent.left) {
RBNode<T> uncle = gparent.right; //获得叔叔节点
//case1: 叔叔节点也是红色
if(uncle != null && isRed(uncle)) {
setBlack(parent); //把父节点和叔叔节点涂黑
setBlack(uncle);
setRed(gparent); //把祖父节点涂红
node = gparent; //将位置放到祖父节点处
continue; //继续while，重新判断
}
//case2: 叔叔节点是黑色，且当前节点是右子节点
if(node == parent.right) {
leftRotate(parent); //从父节点处左旋
RBNode<T> tmp = parent; //然后将父节点和自己调换一下，为下面右旋做准备
parent = node;
node = tmp;
}
//case3: 叔叔节点是黑色，且当前节点是左子节点
setBlack(parent);
setRed(gparent);
rightRotate(gparent);
} else { //若父节点是祖父节点的右子节点,与上面的完全相反，本质一样的
RBNode<T> uncle = gparent.left;
//case1: 叔叔节点也是红色
if(uncle != null & isRed(uncle)) {
setBlack(parent);
setBlack(uncle);
setRed(gparent);
node = gparent;
continue;
}
//case2: 叔叔节点是黑色的，且当前节点是左子节点
if(node == parent.left) {
rightRotate(parent);
RBNode<T> tmp = parent;
parent = node;
node = tmp;
}
//case3: 叔叔节点是黑色的，且当前节点是右子节点
setBlack(parent);
setRed(gparent);
leftRotate(gparent);
}
}
//将根节点设置为黑色
setBlack(this.root);
}
/*********************** 删除红黑树中的节点 **********************/
public void remove(T key) {
RBNode<T> node;
if((node = search(root, key)) != null)
remove(node);
}
private void remove(RBNode<T> node) {
RBNode<T> child, parent;
boolean color;
//1. 被删除的节点“左右子节点都不为空”的情况
if((node.left != null) && (node.right != null)) {
//先找到被删除节点的后继节点，用它来取代被删除节点的位置
RBNode<T> replace = node;
// 1). 获取后继节点
replace = replace.right;
while(replace.left != null)
replace = replace.left;
// 2). 处理“后继节点”和“被删除节点的父节点”之间的关系
if(parentOf(node) != null) { //要删除的节点不是根节点
if(node == parentOf(node).left)
parentOf(node).left = replace;
else
parentOf(node).right = replace;
} else { //否则
this.root = replace;
}
// 3). 处理“后继节点的子节点”和“被删除节点的子节点”之间的关系
child = replace.right; //后继节点肯定不存在左子节点！
parent = parentOf(replace);
color = colorOf(replace);//保存后继节点的颜色
if(parent == node) { //后继节点是被删除节点的子节点
parent = replace;
} else { //否则
if(child != null)
setParent(child, parent);
parent.left = child;
replace.right = node.right;
setParent(node.right, replace);
}
replace.parent = node.parent;
replace.color = node.color; //保持原来位置的颜色
replace.left = node.left;
node.left.parent = replace;
if(color == BLACK) { //4. 如果移走的后继节点颜色是黑色，重新修整红黑树
removeFixUp(child, parent);//将后继节点的child和parent传进去
}
node = null;
return;
}
}
//node表示待修正的节点，即后继节点的子节点（因为后继节点被挪到删除节点的位置去了）
private void removeFixUp(RBNode<T> node, RBNode<T> parent) {
RBNode<T> other;
while((node == null || isBlack(node)) && (node != this.root)) {
if(parent.left == node) { //node是左子节点，下面else与这里的刚好相反
other = parent.right; //node的兄弟节点
if(isRed(other)) { //case1: node的兄弟节点other是红色的
setBlack(other);
setRed(parent);
leftRotate(parent);
other = parent.right;
}
//case2: node的兄弟节点other是黑色的，且other的两个子节点也都是黑色的
if((other.left == null || isBlack(other.left)) &&
(other.right == null || isBlack(other.right))) {
setRed(other);
node = parent;
parent = parentOf(node);
} else {
//case3: node的兄弟节点other是黑色的，且other的左子节点是红色，右子节点是黑色
if(other.right == null || isBlack(other.right)) {
setBlack(other.left);
setRed(other);
rightRotate(other);
other = parent.right;
}
//case4: node的兄弟节点other是黑色的，且other的右子节点是红色，左子节点任意颜色
setColor(other, colorOf(parent));
setBlack(parent);
setBlack(other.right);
leftRotate(parent);
node = this.root;
break;
}
} else { //与上面的对称
other = parent.left;
if (isRed(other)) {
// Case 1: node的兄弟other是红色的
setBlack(other);
setRed(parent);
rightRotate(parent);
other = parent.left;
}
if ((other.left==null || isBlack(other.left)) &&
(other.right==null || isBlack(other.right))) {
// Case 2: node的兄弟other是黑色，且other的俩个子节点都是黑色的
setRed(other);
node = parent;
parent = parentOf(node);
} else {
if (other.left==null || isBlack(other.left)) {
// Case 3: node的兄弟other是黑色的，并且other的左子节点是红色，右子节点为黑色。
setBlack(other.right);
setRed(other);
leftRotate(other);
other = parent.left;
}
// Case 4: node的兄弟other是黑色的；并且other的左子节点是红色的，右子节点任意颜色
setColor(other, colorOf(parent));
setBlack(parent);
setBlack(other.left);
rightRotate(parent);
node = this.root;
break;
}
}
}
if (node!=null)
setBlack(node);
}
/****************** 销毁红黑树 *********************/
public void clear() {
destroy(root);
root = null;
}
private void destroy(RBNode<T> tree) {
if(tree == null)
return;
if(tree.left != null)
destroy(tree.left);
if(tree.right != null)
destroy(tree.right);
tree = null;
}
/******************* 打印红黑树 *********************/
public void print() {
if(root != null) {
print(root, root.key, 0);
}
}
/*
* key---节点的键值
* direction--- 0:表示该节点是根节点
* 1:表示该节点是它的父节点的左子节点
* 2:表示该节点是它的父节点的右子节点
*/
private void print(RBNode<T> tree, T key, int direction) {
if(tree != null) {
if(0 == direction)
System.out.printf("%2d(B) is root\n", tree.key);
else
System.out.printf("%2d(%s) is %2d's %6s child\n",
tree.key, isRed(tree)?"R":"b", key, direction == 1?"right":"left");
print(tree.left, tree.key, -1);
print(tree.right, tree.key, 1);
}
}
}
2、测试
package demo20;
public class RBTreeTest {
private static final int a[] = {10, 40, 30, 60, 90, 70, 20, 50, 80};
private static final boolean mDebugInsert = true; // "插入"动作的检测开关(false，关闭；true，打开)
private static final boolean mDebugDelete = true; // "删除"动作的检测开关(false，关闭；true，打开)
public static void main(String[] args) {
int i, ilen = a.length;
RBTree<Integer> tree = new RBTree<Integer>();
System.out.printf("== 原始数据: ");
for(i=0; i<ilen; i++)
System.out.printf("%d ", a[i]);
System.out.printf("\n");
for(i=0; i<ilen; i++) {
tree.insert(a[i]);
// 设置mDebugInsert=true,测试"添加函数"
if (mDebugInsert) {
System.out.printf("== 添加节点: %d\n", a[i]);
System.out.printf("== 树的详细信息: \n");
tree.print();
System.out.printf("\n");
}
}
System.out.printf("== 前序遍历: ");
tree.preOrder();
System.out.printf("\n== 中序遍历: ");
tree.inOrder();
System.out.printf("\n== 后序遍历: ");
tree.postOrder();
System.out.printf("\n");
System.out.printf("== 最小值: %s\n", tree.minValue());
System.out.printf("== 最大值: %s\n", tree.maxValue());
System.out.printf("== 树的详细信息: \n");
tree.print();
System.out.printf("\n");
// 设置mDebugDelete=true,测试"删除函数"
if (mDebugDelete) {
for(i=0; i<ilen; i++)
{
tree.remove(a[i]);
System.out.printf("== 删除节点: %d\n", a[i]);
System.out.printf("== 树的详细信息: \n");
tree.print();
System.out.printf("\n");
}
}
}
}
执行结果：
== 原始数据: 10 40 30 60 90 70 20 50 80
== 添加节点: 10
== 树的详细信息:
10(B) is root
== 添加节点: 40
== 树的详细信息:
10(B) is root
40(R) is 10's right child
== 添加节点: 30
== 树的详细信息:
30(B) is root
10(R) is 30's left child
40(R) is 30's right child
== 添加节点: 60
== 树的详细信息:
30(B) is root
10(b) is 30's left child
40(b) is 30's right child
60(R) is 40's right child
== 添加节点: 90
== 树的详细信息:
30(B) is root
10(b) is 30's left child
60(b) is 30's right child
40(R) is 60's left child
90(R) is 60's right child
== 添加节点: 70
== 树的详细信息:
30(B) is root
10(b) is 30's left child
60(R) is 30's right child
40(b) is 60's left child
90(b) is 60's right child
70(R) is 90's left child
== 添加节点: 20
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
90(b) is 60's right child
70(R) is 90's left child
== 添加节点: 50
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
50(R) is 40's right child
90(b) is 60's right child
70(R) is 90's left child
== 添加节点: 80
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
50(R) is 40's right child
80(b) is 60's right child
70(R) is 80's left child
90(R) is 80's right child
== 前序遍历: 30 10 20 60 40 50 80 70 90
== 中序遍历: 10 20 30 60 40 50 80 70 90
== 后序遍历: 10 20 60 40 50 80 70 90 30
== 最小值: 10
== 最大值: 90
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
50(R) is 40's right child
80(b) is 60's right child
70(R) is 80's left child
90(R) is 80's right child
== 删除节点: 10
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
50(R) is 40's right child
80(b) is 60's right child
70(R) is 80's left child
90(R) is 80's right child
== 删除节点: 40
== 树的详细信息:
30(B) is root
10(b) is 30's left child
20(R) is 10's right child
60(R) is 30's right child
40(b) is 60's left child
50(R) is 40's right child
80(b) is 60's right child
70(R) is 80's left child
90(R) is 80's right child
== 删除节点: 30
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
60(R) is 40's right child
50(b) is 60's left child
80(b) is 60's right child
70(R) is 80's left child
90(R) is 80's right child
== 删除节点: 60
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
70(R) is 40's right child
50(b) is 70's left child
80(b) is 70's right child
90(R) is 80's right child
== 删除节点: 90
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
70(R) is 40's right child
50(b) is 70's left child
80(b) is 70's right child
90(R) is 80's right child
== 删除节点: 70
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
80(R) is 40's right child
50(b) is 80's left child
90(b) is 80's right child
== 删除节点: 20
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
80(R) is 40's right child
50(b) is 80's left child
90(b) is 80's right child
== 删除节点: 50
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
80(R) is 40's right child
50(b) is 80's left child
90(b) is 80's right child
== 删除节点: 80
== 树的详细信息:
40(B) is root
10(b) is 40's left child
20(R) is 10's right child
90(b) is 40's right child
50(R) is 90's left child
