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蔡茂昌 / Algorithms-implemented-in-Java

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BinaryTree.java 5.76 KB
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蔡茂昌 提交于 2018-04-07 23:41 . Update BinaryTree.java
/**
* This entire class is used to build a Binary Tree data structure.
* There is the Node Class and the Tree Class, both explained below.
*
* @author Unknown
*
*/
/**
* 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;
}
}
/**
* 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
*
*/
class Tree{
/** The root of the Binary Tree */
private Node root;
/**
* Constructor
*/
public Tree(){
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) {
current = current.left;
} else if(key > current.data) {
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.right != null && successor.parent != temp){
successor.right.parent = successor.parent;
successor.parent.left = successor.right;
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 + " ");
}
}
}
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