260 lines
6.6 KiB
Java
260 lines
6.6 KiB
Java
package DataStructures.Trees;
|
|
|
|
/**
|
|
* This entire class is used to build a Binary Tree data structure. There is the Node Class and the
|
|
* Tree Class, both explained below.
|
|
*/
|
|
|
|
/**
|
|
* A binary tree is a data structure in which an element has two successors(children). The left
|
|
* child is usually smaller than the parent, and the right child is usually bigger.
|
|
*
|
|
* @author Unknown
|
|
*/
|
|
public class BinaryTree {
|
|
|
|
/**
|
|
* This class implements the nodes that will go on the Binary Tree. They consist of the data in
|
|
* them, the node to the left, the node to the right, and the parent from which they came from.
|
|
*
|
|
* @author Unknown
|
|
*/
|
|
class Node {
|
|
/** Data for the node */
|
|
public int data;
|
|
/** The Node to the left of this one */
|
|
public Node left;
|
|
/** The Node to the right of this one */
|
|
public Node right;
|
|
/** The parent of this node */
|
|
public Node parent;
|
|
|
|
/**
|
|
* Constructor of Node
|
|
*
|
|
* @param value Value to put in the node
|
|
*/
|
|
public Node(int value) {
|
|
data = value;
|
|
left = null;
|
|
right = null;
|
|
parent = null;
|
|
}
|
|
}
|
|
|
|
/** The root of the Binary Tree */
|
|
private Node root;
|
|
|
|
/** Constructor */
|
|
public BinaryTree() {
|
|
root = null;
|
|
}
|
|
|
|
/**
|
|
* Method to find a Node with a certain value
|
|
*
|
|
* @param key Value being looked for
|
|
* @return The node if it finds it, otherwise returns the parent
|
|
*/
|
|
public Node find(int key) {
|
|
Node current = root;
|
|
while (current != null) {
|
|
if (key < current.data) {
|
|
if (current.left == null) return current; // The key isn't exist, returns the parent
|
|
current = current.left;
|
|
} else if (key > current.data) {
|
|
if (current.right == null) return current;
|
|
current = current.right;
|
|
} else { // If you find the value return it
|
|
return current;
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Inserts certain value into the Binary Tree
|
|
*
|
|
* @param value Value to be inserted
|
|
*/
|
|
public void put(int value) {
|
|
Node newNode = new Node(value);
|
|
if (root == null) root = newNode;
|
|
else {
|
|
// This will return the soon to be parent of the value you're inserting
|
|
Node parent = find(value);
|
|
|
|
// This if/else assigns the new node to be either the left or right child of the parent
|
|
if (value < parent.data) {
|
|
parent.left = newNode;
|
|
parent.left.parent = parent;
|
|
return;
|
|
} else {
|
|
parent.right = newNode;
|
|
parent.right.parent = parent;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Deletes a given value from the Binary Tree
|
|
*
|
|
* @param value Value to be deleted
|
|
* @return If the value was deleted
|
|
*/
|
|
public boolean remove(int value) {
|
|
// temp is the node to be deleted
|
|
Node temp = find(value);
|
|
|
|
// If the value doesn't exist
|
|
if (temp.data != value) return false;
|
|
|
|
// No children
|
|
if (temp.right == null && temp.left == null) {
|
|
if (temp == root) root = null;
|
|
|
|
// This if/else assigns the new node to be either the left or right child of the parent
|
|
else if (temp.parent.data < temp.data) temp.parent.right = null;
|
|
else temp.parent.left = null;
|
|
return true;
|
|
}
|
|
|
|
// Two children
|
|
else if (temp.left != null && temp.right != null) {
|
|
Node successor = findSuccessor(temp);
|
|
|
|
// The left tree of temp is made the left tree of the successor
|
|
successor.left = temp.left;
|
|
successor.left.parent = successor;
|
|
|
|
// If the successor has a right child, the child's grandparent is it's new parent
|
|
if (successor.parent != temp) {
|
|
if (successor.right != null) {
|
|
successor.right.parent = successor.parent;
|
|
successor.parent.left = successor.right;
|
|
successor.right = temp.right;
|
|
successor.right.parent = successor;
|
|
} else {
|
|
successor.parent.left = null;
|
|
successor.right = temp.right;
|
|
successor.right.parent = successor;
|
|
}
|
|
}
|
|
|
|
if (temp == root) {
|
|
successor.parent = null;
|
|
root = successor;
|
|
return true;
|
|
}
|
|
|
|
// If you're not deleting the root
|
|
else {
|
|
successor.parent = temp.parent;
|
|
|
|
// This if/else assigns the new node to be either the left or right child of the parent
|
|
if (temp.parent.data < temp.data) temp.parent.right = successor;
|
|
else temp.parent.left = successor;
|
|
return true;
|
|
}
|
|
}
|
|
// One child
|
|
else {
|
|
// If it has a right child
|
|
if (temp.right != null) {
|
|
if (temp == root) {
|
|
root = temp.right;
|
|
return true;
|
|
}
|
|
|
|
temp.right.parent = temp.parent;
|
|
|
|
// Assigns temp to left or right child
|
|
if (temp.data < temp.parent.data) temp.parent.left = temp.right;
|
|
else temp.parent.right = temp.right;
|
|
return true;
|
|
}
|
|
// If it has a left child
|
|
else {
|
|
if (temp == root) {
|
|
root = temp.left;
|
|
return true;
|
|
}
|
|
|
|
temp.left.parent = temp.parent;
|
|
|
|
// Assigns temp to left or right side
|
|
if (temp.data < temp.parent.data) temp.parent.left = temp.left;
|
|
else temp.parent.right = temp.left;
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* This method finds the Successor to the Node given. Move right once and go left down the tree as
|
|
* far as you can
|
|
*
|
|
* @param n Node that you want to find the Successor of
|
|
* @return The Successor of the node
|
|
*/
|
|
public Node findSuccessor(Node n) {
|
|
if (n.right == null) return n;
|
|
Node current = n.right;
|
|
Node parent = n.right;
|
|
while (current != null) {
|
|
parent = current;
|
|
current = current.left;
|
|
}
|
|
return parent;
|
|
}
|
|
|
|
/**
|
|
* Returns the root of the Binary Tree
|
|
*
|
|
* @return the root of the Binary Tree
|
|
*/
|
|
public Node getRoot() {
|
|
return root;
|
|
}
|
|
|
|
/**
|
|
* Prints leftChild - root - rightChild
|
|
*
|
|
* @param localRoot The local root of the binary tree
|
|
*/
|
|
public void inOrder(Node localRoot) {
|
|
if (localRoot != null) {
|
|
inOrder(localRoot.left);
|
|
System.out.print(localRoot.data + " ");
|
|
inOrder(localRoot.right);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Prints root - leftChild - rightChild
|
|
*
|
|
* @param localRoot The local root of the binary tree
|
|
*/
|
|
public void preOrder(Node localRoot) {
|
|
if (localRoot != null) {
|
|
System.out.print(localRoot.data + " ");
|
|
preOrder(localRoot.left);
|
|
preOrder(localRoot.right);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Prints rightChild - leftChild - root
|
|
*
|
|
* @param localRoot The local root of the binary tree
|
|
*/
|
|
public void postOrder(Node localRoot) {
|
|
if (localRoot != null) {
|
|
postOrder(localRoot.left);
|
|
postOrder(localRoot.right);
|
|
System.out.print(localRoot.data + " ");
|
|
}
|
|
}
|
|
}
|