红黑树实现（Java语言）

最近在看红黑树，也想自己写程序实现一下，因为红黑树的删除还没有看，所以程序中并没有包含删除操作，等看完了再补上，呵呵。。。

至于红黑树的原理我就不多说了，我是参考<算法导论>中的伪代码写的程序。

代码实现如下：

package com.datastructure.tree;public class MyRbTree {RbTreeNode root=null;RbTreeNode nilNode=null;public RbTreeNode getRoot() {return root;}public MyRbTree(){this.nilNode=new RbTreeNode(-1);this.nilNode.color=TreeNodeColor.Black;this.nilNode.left=null;this.nilNode.right=null;this.nilNode.parent=null;this.root=this.nilNode;}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubMyRbTree mytree=new MyRbTree();int[] array={2,5,3,4,1,0};for(int i=0;i<array.length;i++){mytree.insert(array[i]);mytree.preorder(mytree.getRoot());System.out.println();}}private void leftRotate(MyRbTree tree,RbTreeNode x){RbTreeNode y=x.right;x.right=y.left;y.left.parent=x;y.parent=x.parent;if(x.parent==this.nilNode){tree.root=y;}else{if(x==x.parent.left)x.parent.left=y;elsex.parent.right=y;}y.left=x;x.parent=y;}private void rightRotate(MyRbTree tree,RbTreeNode y){RbTreeNode x=y.left;y.left=x.right;x.right.parent=y;x.parent=y.parent;if(y.parent==this.nilNode){tree.root=x;}else{if(y==y.parent.left)y.parent.left=x;elsey.parent.right=x;}x.right=y;y.parent=x;}private void insert(MyRbTree tree,int value){RbTreeNode y=this.nilNode;RbTreeNode x=tree.root;RbTreeNode z=new RbTreeNode(value);while(x!=this.nilNode){y=x;if(value<x.key)x=x.left;elsex=x.right;}z.parent=y;if(y==this.nilNode){tree.root=z;}else{if(value<y.key){y.left=z;}else{y.right=z;}}z.left=this.nilNode;z.right=this.nilNode;insertFixUp(tree,z);}public void insert(int value){insert(this,value);}private void insertFixUp(MyRbTree tree,RbTreeNode z){while(z.parent.color==TreeNodeColor.Red){if(z.parent==z.parent.parent.left){RbTreeNode uncle=z.parent.parent.right;if(uncle.color==TreeNodeColor.Red){z.parent.color=TreeNodeColor.Black;uncle.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;z=z.parent.parent;}else{if(z==z.parent.right){z=z.parent;leftRotate(tree,z);}z.parent.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;rightRotate(tree,z.parent.parent);}}else if(z.parent==z.parent.parent.right){RbTreeNode uncle=z.parent.parent.left;if(uncle.color==TreeNodeColor.Red){z.parent.color=TreeNodeColor.Black;uncle.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;z=z.parent.parent;}else{if(z==z.parent.left){z=z.parent;rightRotate(tree,z);}z.parent.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;leftRotate(tree,z.parent.parent);}}}tree.root.color=TreeNodeColor.Black;}public void preorder(RbTreeNode root){if(root!=null){preorder(root.left);getNodeInfo(root);preorder(root.right);}}public void getNodeInfo(RbTreeNode node){if(node!=this.nilNode){System.out.println(node.key+" "+node.color.toString());}}}class RbTreeNode{TreeNodeColor color=TreeNodeColor.Red;int key=-1;RbTreeNode left=null;RbTreeNode right=null;RbTreeNode parent=null;public RbTreeNode(int value){this.key=value;}}

运行结果如下所示：

2 Black2 Black5 Red2 Red3 Black5 Red2 Black3 Black4 Red5 Black1 Red2 Black3 Black4 Red5 Black0 Red1 Black2 Red3 Black4 Red5 Black

从运行结果可以看出程序是没有问题的。有改进的地方大家可以提啊，谢谢！

今天看了看算法导论中关于红黑树删除的有关知识，自己实现了一下，现添加到上面的程序中，程序代码和运行结果如下所示，我是严格按照算法导论的伪代码写的，相信大家可以看得很清楚。

package com.datastructure.tree;public class MyRbTree {RbTreeNode root=null;RbTreeNode nilNode=null;public RbTreeNode getRoot() {return root;}public MyRbTree(){this.nilNode=new RbTreeNode(-1);this.nilNode.color=TreeNodeColor.Black;this.nilNode.left=null;this.nilNode.right=null;this.nilNode.parent=null;this.root=this.nilNode;}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubMyRbTree mytree=new MyRbTree();int[] array={41,38,31,12,19,8};for(int i=0;i<array.length;i++){System.out.println("插入"+array[i]);mytree.insert(array[i]);mytree.preorder(mytree.getRoot());System.out.println();}for(int i=5;i>=0;i--){System.out.println("删除"+array[i]);mytree.delete(array[i]);mytree.preorder(mytree.getRoot());System.out.println();}}private void leftRotate(MyRbTree tree,RbTreeNode x){RbTreeNode y=x.right;x.right=y.left;y.left.parent=x;y.parent=x.parent;if(x.parent==this.nilNode){tree.root=y;}else{if(x==x.parent.left)x.parent.left=y;elsex.parent.right=y;}y.left=x;x.parent=y;}private void rightRotate(MyRbTree tree,RbTreeNode y){RbTreeNode x=y.left;y.left=x.right;x.right.parent=y;x.parent=y.parent;if(y.parent==this.nilNode){tree.root=x;}else{if(y==y.parent.left)y.parent.left=x;elsey.parent.right=x;}x.right=y;y.parent=x;}private void insert(MyRbTree tree,int value){RbTreeNode y=this.nilNode;RbTreeNode x=tree.root;RbTreeNode z=new RbTreeNode(value);while(x!=this.nilNode){y=x;if(value<x.key)x=x.left;elsex=x.right;}z.parent=y;if(y==this.nilNode){tree.root=z;}else{if(value<y.key){y.left=z;}else{y.right=z;}}z.left=this.nilNode;z.right=this.nilNode;insertFixUp(tree,z);}public void insert(int value){insert(this,value);}private RbTreeNode search(MyRbTree tree,int value){RbTreeNode node=tree.root;while((node!=tree.nilNode)&&(node.key!=value)){if(value<node.key){node=node.left;}else{node=node.right;}}return node;}public boolean search(int value){if(search(this,value)!=this.nilNode)return true;elsereturn false;}public RbTreeNode minimum(RbTreeNode x){while(x.left!=this.nilNode){x=x.left;}return x;}public RbTreeNode successor(RbTreeNode x){if(x.right!=this.nilNode){return minimum(x.right);}RbTreeNode y=x.parent;while(y!=this.nilNode&&x==y.right){x=y;y=y.parent;}return y;}private boolean delete(MyRbTree tree,int value){RbTreeNode z=search(tree,value);if(z==tree.nilNode){return false;}RbTreeNode y=null;if(z.left==tree.nilNode||z.right==tree.nilNode){y=z;}else{y=successor(z);}RbTreeNode x=null;if(y.left!=tree.nilNode){x=y.left;}else{x=y.right;}x.parent=y.parent;if(y.parent==tree.nilNode){this.root=x;}else{if(y==y.parent.left){y.parent.left=x;}else{y.parent.right=x;}}if(y!=z){z.key=y.key;}if(y.color==TreeNodeColor.Black){deleteFixUp(tree,x);}return true;}private void deleteFixUp(MyRbTree tree,RbTreeNode x){while(x!=tree.root&&x.color==TreeNodeColor.Black){if(x==x.parent.left){RbTreeNode w=x.parent.right;if(w.color==TreeNodeColor.Red){w.color=TreeNodeColor.Black;x.color=TreeNodeColor.Red;leftRotate(tree,x.parent);w=x.parent.right;}if(w.left.color==TreeNodeColor.Black&&w.right.color==TreeNodeColor.Black){w.color=TreeNodeColor.Red;x=x.parent;}else{if(w.right.color==TreeNodeColor.Black){w.left.color=TreeNodeColor.Black;w.color=TreeNodeColor.Red;rightRotate(tree,w);w=x.parent.right;}w.color=x.parent.color;x.parent.color=TreeNodeColor.Black;w.right.color=TreeNodeColor.Black;leftRotate(tree,x.parent);x=tree.root;}}else{RbTreeNode w=x.parent.left;if(w.color==TreeNodeColor.Red){w.color=TreeNodeColor.Black;x.color=TreeNodeColor.Red;rightRotate(tree,x.parent);w=x.parent.left;}if(w.left.color==TreeNodeColor.Black&&w.right.color==TreeNodeColor.Black){w.color=TreeNodeColor.Red;x=x.parent;}else{if(w.left.color==TreeNodeColor.Black){w.right.color=TreeNodeColor.Black;w.color=TreeNodeColor.Red;leftRotate(tree,w);w=x.parent.left;}w.color=x.parent.color;x.parent.color=TreeNodeColor.Black;w.left.color=TreeNodeColor.Black;leftRotate(tree,x.parent);x=tree.root;}}}x.color=TreeNodeColor.Black;}public boolean delete(int value){return delete(this,value);}private void insertFixUp(MyRbTree tree,RbTreeNode z){while(z.parent.color==TreeNodeColor.Red){if(z.parent==z.parent.parent.left){RbTreeNode uncle=z.parent.parent.right;if(uncle.color==TreeNodeColor.Red){z.parent.color=TreeNodeColor.Black;uncle.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;z=z.parent.parent;}else{if(z==z.parent.right){z=z.parent;leftRotate(tree,z);}z.parent.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;rightRotate(tree,z.parent.parent);}}else if(z.parent==z.parent.parent.right){RbTreeNode uncle=z.parent.parent.left;if(uncle.color==TreeNodeColor.Red){z.parent.color=TreeNodeColor.Black;uncle.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;z=z.parent.parent;}else{if(z==z.parent.left){z=z.parent;rightRotate(tree,z);}z.parent.color=TreeNodeColor.Black;z.parent.parent.color=TreeNodeColor.Red;leftRotate(tree,z.parent.parent);}}}tree.root.color=TreeNodeColor.Black;}public void preorder(RbTreeNode root){if(root!=null){preorder(root.left);getNodeInfo(root);preorder(root.right);}}public void getNodeInfo(RbTreeNode node){if(node!=this.nilNode){System.out.println(node.key+" "+node.color.toString());}}}class RbTreeNode{TreeNodeColor color=TreeNodeColor.Red;int key=-1;RbTreeNode left=null;RbTreeNode right=null;RbTreeNode parent=null;public RbTreeNode(int value){this.key=value;}}

运行结果如下所示：

插入4141 Black插入3838 Red41 Black插入3131 Red38 Black41 Red插入1212 Red31 Black38 Black41 Black插入1912 Red19 Black31 Red38 Black41 Black插入88 Red12 Black19 Red31 Black38 Black41 Black删除812 Black19 Red31 Black38 Black41 Black删除1912 Red31 Black38 Black41 Black删除1231 Black38 Black41 Black删除3138 Black41 Red删除3841 Black删除41

我自己用纸也画了下插入和删除的红黑树图，跟运行的结果中每个节点的颜色都是吻合的，个人觉得是没有什么问题的，如果有什么问题，欢迎讨论，谢谢....