From 50436468d33f5d74b56820c120fad5098c6e26df Mon Sep 17 00:00:00 2001
From: marina <138340846+bt3gl-cryptographer@users.noreply.github.com>
Date: Thu, 3 Aug 2023 15:37:11 -0700
Subject: [PATCH] add avl tree class

---
 trees/bst_avl.py | 155 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 trees/bst_avl.py

diff --git a/trees/bst_avl.py b/trees/bst_avl.py
new file mode 100644
index 0000000..134587f
--- /dev/null
+++ b/trees/bst_avl.py
@@ -0,0 +1,155 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+class Node():
+    def __init__(self, val):
+        self.val = val
+        self.left = None
+        self.right = None
+        self.height = 1
+
+
+class AVLTree():
+  
+    def __init__(self):
+        self.root = None
+        self.size = 0
+				
+    def height(self, node):
+        if node:
+            return node.height
+        return 0
+		
+    def set_height(self, node):
+        if node is None:
+            return 0
+        return 1 + max(self.height(node.left), self.height(node.right))
+		
+    def right_rotate(self, node):
+        new_root = node.left
+        node.left = node.left.right
+        new_root.right = node
+        node.height = self.set_height(node)
+        new_root.height = self.set_height(new_root)
+        return new_root
+    
+    def left_rotate(self, node):
+        new_root = node.right
+        node.right = node.right.left
+        new_root.left = node
+        node.height = self.set_height(node)
+        new_root.height = self.set_height(new_root)
+        return new_root
+        
+    def insert(self, node, val):
+        if node == self.root:
+            self.size += 1
+        if node is None:
+            return Node(val)
+        if node.val < val:
+            node.right = self.insert(node.right, val)
+        else:
+            node.left = self.insert(node.left, val)
+        balance = self.height(node.left) - self.height(node.right)
+        if balance > 1:
+            if self.height(node.left.left) > self.height(node.left.right):
+                node = self.right_rotate(node)
+            else:
+                node.left = self.left_rotate(node.left)
+                node = self.right_rotate(node)
+        elif balance < -1:
+            if self.height(node.right.right) > self.height(node.right.left):
+                node = self.left_rotate(node)
+            else:
+                node.right = self.right_rotate(node.right)
+                node = self.left_rotate(node)
+        else:
+            node.height = self.set_height(node)
+        return node
+    
+    def get_min_val(self, node):
+        if node is None or node.left is None:
+            return node
+        return self.get_min_val(node.left)
+    
+    def remove(self, node, val):
+        if node is None:
+            return node
+        if node.val < val:
+            node.right = self.remove(node.right, val)
+        elif node.val > val:
+            node.left = self.remove(node.left, val)
+        else:
+            if node.left is None:
+                return node.right
+            elif node.right is None:
+                return node.left
+            else:
+                right_min_val_node = self.get_min_val(node.right)
+                node.val = right_min_val_node.val
+                node.right = self.remove(node.right, right_min_val_node.val)
+        
+        node.height = self.set_height(node)
+        balance = self.height(node.left) - self.height(node.right)
+        if balance > 1:
+            if self.height(node.left.left) > self.height(node.left.right):
+                node = self.right_rotate(node)
+            else:
+                node.left = self.left_rotate(node.left)
+                node = self.right_rotate(node)
+        elif balance < -1:
+            if self.height(node.right.right) > self.height(node.right.left):
+                node = self.left_rotate(node)
+            else:
+                node.right = self.right_rotate(node.right)
+                node = self.left_rotate(node)
+        else:
+            node.height = self.set_height(node)
+        return node
+    
+    def predecessor(self, node, val):
+        if node is None:
+            return node
+        if node.val == val:
+            return val
+        elif node.val > val:
+            return self.predecessor(node.left, val)
+        else:
+            right_res = self.predecessor(node.right, val)
+            return right_res if right_res else node.val    
+            
+    def successor(self, node, val):
+        if node is None:
+            return node
+        if node.val == val:
+            return val
+        elif node.val < val:
+            return self.successor(node.right, val)
+        else:
+            left_res = self.successor(node.left, val)
+            return left_res if left_res else node.val
+
+
+def contains_duplicate_near(self, nums, k, t):
+
+        avltree = AVLTree()
+        root = avltree.root
+
+  
+        for i, num in enumerate(nums):            
+            predecessor = avltree.predecessor(root, num)
+            if predecessor is not None and abs(predecessor - num) <= t:
+                return True
+            successor = avltree.successor(root, num)
+            if successor is not None and abs(successor - num) <= t:
+                return True
+                        
+            root = avltree.insert(root, num)
+            
+            if avltree.size > k:
+                root = avltree.remove(root, nums[i-k])
+                
+        return False
+