Java实现红黑树

参考了算法导论，没有设置标兵作为外部节点，所以主要注意下空指针情况，红黑树的删除算法是真的吊

package qiuzhao;public class RBTree<T extends Comparable<T>> {private static final boolean red = true;private static final boolean black = false;private RBNode<T> root;class RBNode<T extends Comparable<T>> {private T key;private boolean color;private RBNode<T> left;private RBNode<T> right;private RBNode<T> parent;public RBNode(T key, boolean color, RBNode<T> left, RBNode<T> right, RBNode<T> parent) {super();this.key = key;this.color = color;this.left = left;this.right = right;this.parent = parent;}public T getKey() {return key;}public void setKey(T key) {this.key = key;}public boolean isColor() {return color;}public void setColor(boolean color) {this.color = color;}public RBNode<T> getLeft() {return left;}public void setLeft(RBNode<T> left) {this.left = left;}public RBNode<T> getRight() {return right;}public void setRight(RBNode<T> right) {this.right = right;}public RBNode<T> getParent() {return parent;}public void setParent(RBNode<T> parent) {this.parent = parent;}}public void insert(T key) {RBNode<T> node = new RBNode<T>(key, black, null, null, null);// 如果新建结点失败，则返回。if (node != null)insert(node);}public void delete(T key) {RBNode<T> node;if ((node = search(root, key)) != null)delete(node);}private RBNode<T> search(RBNode<T> x, T key) {if (x == null)return x;int cmp = key.compareTo(x.key);if (cmp < 0)return search(x.left, key);else if (cmp > 0)return search(x.right, key);elsereturn x;}private void print(RBNode<T> tree, T key, int direction) {if (tree != null) {if (direction == 0) // tree是根节点System.out.printf("%2d(B) is root\n", tree.key);else // tree是分支节点System.out.printf("%2d(%s) is %2d's %6s child\n", tree.key, tree.color == red ? "R" : "B", key,direction == 1 ? "right" : "left");print(tree.left, tree.key, -1);print(tree.right, tree.key, 1);}}public void print() {if (root != null)print(root, root.key, 0);}public void leftRotate(RBNode<T> x) {RBNode<T> y = x.right;x.right = y.left;if (y.left != null) {y.left.parent = x;}y.parent = x.parent;if (x.parent == null)this.root = y;else {if (x == x.parent.left)x.parent.left = y;elsex.parent.right = y;}y.left = x;x.parent = y;}public void rightRotate(RBNode<T> y) {RBNode<T> x = y.left;y.left = x.right;if (x.right != null)x.right.parent = y;x.parent = y.parent;if (y.parent == null)this.root = x;if (y == y.parent.left)y.parent.left = x;elsey.parent.right = x;y.parent = x;x.right = y;}public void insert(RBNode<T> z) {int cmp = 0;RBNode<T> pre = null;RBNode<T> p = this.root;while (p != null) {pre = p;cmp = p.key.compareTo(z.key);if (cmp < 0)p = p.right;elsep = p.left;}z.parent = pre;if (pre != null) {cmp = pre.key.compareTo(z.key);if (cmp < 0)pre.right = z;elsepre.left = z;} elsethis.root = z;z.color = red;insertFixUp(z);}private void insertFixUp(RBTree<T>.RBNode<T> z) {/* * 循环不变式： * 1、结点z一定是红色的 * 2、如果z.p是根节点，则z.p是黑色的 * 3、如果有任何红黑性质被破坏，则最对只有一条被破坏，或是性质2，或是性质4，如果性质2被破坏，其原因为z是根节点且是红结点； * 如果性质4被破坏，其原因为z和z.p都是红色的。 */while (z.parent != null && z.parent.color == red) {if ( z.parent == z.parent.parent.left) {//z.p.p一定不为空RBNode<T> uncle = z.parent.parent.right;if (uncle != null && uncle.color == red) {//uncle是红色的z.parent.color = black;uncle.color = black;z.parent.parent.color = red;z = z.parent.parent;} else {if (z == z.parent.right) {//uncle是黑色的，并且z是右孩子z = z.parent;leftRotate(z);} else {//uncle是黑色的，并且z是左孩子z.parent.color = black;z.parent.parent.color = red;rightRotate(z.parent.parent);}}} else if (z.parent == z.parent.parent.right) {RBNode<T> uncle = z.parent.parent.left;if (uncle != null && uncle.color == red) {z.parent.color = black;uncle.color = black;z.parent.parent.color = red;z = z.parent.parent;} else {if (z == z.parent.left) {z = z.parent;rightRotate(z);} else {z.parent.color = black;z.parent.parent.color = red;leftRotate(z.parent.parent);}}}}this.root.color = black;}private void transplant(RBNode<T> u, RBNode<T> v) {if (u.parent == null)root = v;else if (u == u.parent.left)u.parent.left = v;elseu.parent.right = v;if (v != null)v.parent = u.parent;}private RBNode<T> minimum(RBNode<T> x) {while (x != null && x.left != null) {x = x.left;}return x;}private RBNode<T> maximum(RBNode<T> x) {while (x != null && x.right != null) {x = x.right;}return x;}public void delete(RBNode<T> z) {RBNode<T> y = z;boolean y_o_color = y.color;RBNode<T> x = null;if (z.left == null) {x = z.right;transplant(z, z.right);} else if (z.right == null) {x = z.left;transplant(z, z.left);} else {y = minimum(z.right);y_o_color = y.color;x = y.right;//if (y.parent == z)//x.parent = y;//else {if(y.parent != z){transplant(y, y.right);y.right = z.right;y.right.parent = y;}transplant(z, y);y.left = z.left;z.left.parent = y;y.color = z.color;}if (y_o_color == black)delete_fixup(x);}private void delete_fixup(RBTree<T>.RBNode<T> x) {// TODO Auto-generated method stubwhile (x != root && x!= null && x.color == black) {if (x.parent != null && x == x.parent.left) {RBNode<T> bro = x.parent.right;if (bro != null && bro.color == red) {//bro为红色bro.color = black;x.parent.color = red;leftRotate(x.parent);bro = x.parent.right;}if ((bro.left == null || bro.left.color == black) && (bro.right == null || bro.right.color == black)) {//bro为黑色，而且bro的两个子结点为黑色bro.color = red;x = x.parent;} else {if (bro.right == null || bro.right.color == black) {//bro为黑色，bro左孩子为红色，bro右孩子为黑色bro.left.color = black;bro.color = red;rightRotate(bro);bro = x.parent.right;}//bro为黑色，bro右孩子为红色。bro.color = x.parent.color;x.parent.color = black;bro.right.color = black;leftRotate(x.parent);x = root;}} else if(x.parent != null && x == x.parent.right){RBNode<T> bro = x.parent.left;if (bro != null && bro.color == red) {bro.color = black;x.parent.color = red;rightRotate(x.parent);bro = x.parent.left;}if ((bro.right == null || bro.right.color == black) && (bro.left == null || bro.left.color == black)) {bro.color = red;x = x.parent;} else {if (bro.left == null || bro.left.color == black) {bro.right.color = black;bro.color = red;leftRotate(bro);bro = x.parent.left;}bro.color = x.parent.color;x.parent.color = black;bro.left.color = black;leftRotate(x.parent);x = root;}}}if (x != null)x.color = black;}public void inorderTra() {inorderTra(this.root);}private void inorderTra(RBNode<T> node) {if (node == null)return;inorderTra(node.left);System.out.println(node.key);inorderTra(node.right);}}

package qiuzhao;/** * Java 语言: 二叉查找树 * * @author skywang * @date 2013/11/07 */public class RBTreeTest {    private static final int a[] = {10, 40, 30, 60, 90, 70, 20, 50, 80};    private static  boolean mDebugInsert = false;    // "插入"动作的检测开关(false，关闭；true，打开)    private static  boolean mDebugDelete = false;    // "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");        mDebugInsert=true;        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("\n== 中序遍历: ");        tree.inorderTra();        System.out.printf("\n");        // 设置mDebugDelete=true,测试"删除函数"        mDebugDelete=true;        if (mDebugDelete) {            for(i=0; i<ilen; i++)            {                tree.delete(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");            }        }    }}

参考链接：http://www.cnblogs.com/skywang12345/p/3624343.html