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Copy pathAVLTree.java
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113 lines (87 loc) · 2.89 KB
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package com.hellokoding.datastructure;
public class AVLTree {
public Node root;
private int findHeight(Node node) {
return node == null ? -1 : node.height;
}
private int findBalanceFactor(Node node) {
return node == null ? 0 : (findHeight(node.left) - findHeight(node.right));
}
private Node rotateRight(Node node) {
Node pivot = node.left;
node.left = pivot.right;
pivot.right = node;
node.height = 1 + Math.max(findHeight(node.left), findHeight(node.right));
pivot.height = 1 + Math.max(findHeight(pivot.left), findHeight(pivot.right));
return pivot;
}
private Node rotateLeft(Node node) {
Node pivot = node.right;
node.right = pivot.left;
pivot.left = node;
node.height = 1 + Math.max(findHeight(node.left), findHeight(node.right));
pivot.height = 1 + Math.max(findHeight(pivot.left), findHeight(pivot.right));
return pivot;
}
private Node insert(Node node, int key) {
if (node == null) {
return new Node(key);
}
if (key < node.key) {
node.left = insert(node.left, key);
} else if (key > node.key) {
node.right = insert(node.right, key);
} else {
return node;
}
node.height = 1 + Math.max(findHeight(node.left), findHeight(node.right));
int balanceFactor = findBalanceFactor(node);
if (balanceFactor > 1 && key < node.left.key) {
return rotateRight(node);
}
if (balanceFactor < - 1 && key > node.right.key) {
return rotateLeft(node);
}
if (balanceFactor > 1 && key > node.left.key) {
node.left = rotateLeft(node.left);
return rotateRight(node);
}
if (balanceFactor < -1 && key < node.right.key) {
node.right = rotateRight(node.right);
return rotateLeft(node);
}
return node;
}
public void insert(int data) {
this.root = insert(this.root, data);
}
public void inTraversal(Node node) {
if (node == null) return;
inTraversal(node.left);
System.out.println(node);
inTraversal(node.right);
}
public static void main(String[] args) {
AVLTree tree = new AVLTree();
tree.insert(7);
tree.insert(2);
tree.insert(3);
tree.insert(1);
tree.insert(9);
tree.inTraversal(tree.root);
}
public static class Node {
int key;
int height;
Node left;
Node right;
Node(int key) {
this.key = key;
this.height = 0;
}
@Override
public String toString() {
return String.format("key: %d, height: %d, left: %d, right: %d", key, height, (left !=null ? left.key : null), (right != null? right.key : null));
}
}
}