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RedBlackBST.java

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/**

*

* @author jack870131

*/

public class RedBlackBST {

private final int R = 0;

private final int B = 1;

private class Node {

int key = -1, color = B;

Node left = nil, right = nil, p = nil;

Node(int key) {

this.key = key;

}

}

private final Node nil = new Node(-1);

private Node root = nil;

public void printTree(Node node) {

if (node == nil) {

return;

}

printTree(node.left);

System.out.print(((node.color == R) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");

printTree(node.right);

}

public void printTreepre(Node node) {

if (node == nil) {

return;

}

System.out.print(((node.color == R) ? " R " : " B ") + "Key: " + node.key + " Parent: " + node.p.key + "\n");

printTree(node.left);

printTree(node.right);

}

private Node findNode(Node findNode, Node node) {

if (root == nil) {

return null;

}

if (findNode.key < node.key) {

if (node.left != nil) {

return findNode(findNode, node.left);

}

} else if (findNode.key > node.key) {

if (node.right != nil) {

return findNode(findNode, node.right);

}

} else if (findNode.key == node.key) {

return node;

}

return null;

}

private void insert(Node node) {

Node temp = root;

if (root == nil) {

root = node;

node.color = B;

node.p = nil;

} else {

node.color = R;

while (true) {

if (node.key < temp.key) {

if (temp.left == nil) {

temp.left = node;

node.p = temp;

break;

} else {

temp = temp.left;

}

} else if (node.key >= temp.key) {

if (temp.right == nil) {

temp.right = node;

node.p = temp;

break;

} else {

temp = temp.right;

}

}

}

fixTree(node);

}

}

private void fixTree(Node node) {

while (node.p.color == R) {

Node y = nil;

if (node.p == node.p.p.left) {

y = node.p.p.right;

if (y != nil && y.color == R) {

node.p.color = B;

y.color = B;

node.p.p.color = R;

node = node.p.p;

continue;

}

if (node == node.p.right) {

node = node.p;

rotateLeft(node);

}

node.p.color = B;

node.p.p.color = R;

rotateRight(node.p.p);

} else {

y = node.p.p.left;

if (y != nil && y.color == R) {

node.p.color = B;

y.color = B;

node.p.p.color = R;

node = node.p.p;

continue;

}

if (node == node.p.left) {

node = node.p;

rotateRight(node);

}

node.p.color = B;

node.p.p.color = R;

rotateLeft(node.p.p);

}

}

root.color = B;

}

void rotateLeft(Node node) {

if (node.p != nil) {

if (node == node.p.left) {

node.p.left = node.right;

} else {

node.p.right = node.right;

}

node.right.p = node.p;

node.p = node.right;

if (node.right.left != nil) {

node.right.left.p = node;

}

node.right = node.right.left;

node.p.left = node;

} else {

Node right = root.right;

root.right = right.left;

right.left.p = root;

root.p = right;

right.left = root;

right.p = nil;

root = right;

}

}

void rotateRight(Node node) {

if (node.p != nil) {

if (node == node.p.left) {

node.p.left = node.left;

} else {

node.p.right = node.left;

}

node.left.p = node.p;

node.p = node.left;

if (node.left.right != nil) {

node.left.right.p = node;

}

node.left = node.left.right;

node.p.right = node;

} else {

Node left = root.left;

root.left = root.left.right;

left.right.p = root;

root.p = left;

left.right = root;

left.p = nil;

root = left;

}

}

void transplant(Node target, Node with) {

if (target.p == nil) {

root = with;

} else if (target == target.p.left) {

target.p.left = with;

} else

target.p.right = with;

with.p = target.p;

}

Node treeMinimum(Node subTreeRoot) {

while (subTreeRoot.left != nil) {

subTreeRoot = subTreeRoot.left;

}

return subTreeRoot;

}

boolean delete(Node z) {

if ((z = findNode(z, root)) == null)

return false;

Node x;

Node y = z;

int yorigcolor = y.color;

if (z.left == nil) {

x = z.right;

transplant(z, z.right);

} else if (z.right == nil) {

x = z.left;

transplant(z, z.left);

} else {

y = treeMinimum(z.right);

yorigcolor = y.color;

x = y.right;

if (y.p == z)

x.p = y;

else {

transplant(y, y.right);

y.right = z.right;

y.right.p = y;

}

transplant(z, y);

y.left = z.left;

y.left.p = y;

y.color = z.color;

}

if (yorigcolor == B)

deleteFixup(x);

return true;

}

void deleteFixup(Node x) {

while (x != root && x.color == B) {

if (x == x.p.left) {

Node w = x.p.right;

if (w.color == R) {

w.color = B;

x.p.color = R;

rotateLeft(x.p);

w = x.p.right;

}

if (w.left.color == B && w.right.color == B) {

w.color = R;

x = x.p;

continue;

} else if (w.right.color == B) {

w.left.color = B;

w.color = R;

rotateRight(w);

w = x.p.right;

}

if (w.right.color == R) {

w.color = x.p.color;

x.p.color = B;

w.right.color = B;

rotateLeft(x.p);

x = root;

}

} else {

Node w = x.p.left;

if (w.color == R) {

w.color = B;

x.p.color = R;

rotateRight(x.p);

w = x.p.left;

}

if (w.right.color == B && w.left.color == B) {

w.color = R;

x = x.p;

continue;

} else if (w.left.color == B) {

w.right.color = B;

w.color = R;

rotateLeft(w);

w = x.p.left;

}

if (w.left.color == R) {

w.color = x.p.color;

x.p.color = B;

w.left.color = B;

rotateRight(x.p);

x = root;

}

}

}

x.color = B;

}

public void insertDemo() {

Scanner scan = new Scanner(System.in);

while (true) {

System.out.println("Add items");

int item;

Node node;

item = scan.nextInt();

while (item != -999) {

node = new Node(item);

insert(node);

item = scan.nextInt();

}

printTree(root);

System.out.println("Pre order");

printTreepre(root);

break;

}

}

public void deleteDemo() {

Scanner scan = new Scanner(System.in);

System.out.println("Delete items");

int item;

Node node;

item = scan.nextInt();

node = new Node(item);

System.out.print("Deleting item " + item);

if (delete(node)) {

System.out.print(": deleted!");

} else {

System.out.print(": does not exist!");

}

System.out.println();

printTree(root);

System.out.println("Pre order");

printTreepre(root);

}

}