Create hash_set_bst.py

arrays_and_strings/hash_set_bst.py

@@ -0,0 +1,101 @@
+class HashSet:
+
+    def __init__(self):
+        self.key_range = 131
+        self.bucket = [Bucket() for _ in range(self.key_range)]
+
+    def _hash(self, key):
+        return key % self.key_range
+
+    def add(self, element: int) -> None:
+        bucket_index = self._hash(element)
+        self.bucket[bucket_index].insert(element)
+    
+    def remove(self, element: int) -> None:
+        bucket_index = self._hash(element)
+        self.bucket[bucket_index].delete(element)
+
+    def contains(self, element: int) -> bool:
+        bucket_index = self._hash(element)
+        return self.bucket[bucket_index].exists(element)
+        
+
+class TreeNode:
+    def __init__(self, value=None):
+        self.val = value
+        self.left = None
+        self.right = None
+
+
+class Bucket:
+    def __init__(self):
+        self.tree = BSTree()
+
+    def insert(self, value):
+        self.tree.root = self.tree.insert(self.tree.root, value)
+        
+    def delete(self, value):
+        self.tree.root = self.tree.delete(self.tree.root, value)
+    
+    def exists(self, value):
+        return (self.tree.search(self.tree.root, value) is not None)
+
+
+class BSTree():
+    def __init__(self):
+        self.root = None
+
+    def search(self, root, value) -> TreeNode:
+        if root is None or value == root.val:
+            return root
+
+        return self.search(root.left, value) if val < root.value \
+            else self.search(root.right, value)
+    
+    def insert(self, root, value) -> TreeNode:
+        if not root:
+            return TreeNode(value)
+        
+        if value > root.val:
+            root.right = self.insert(root.right, value)
+        elif value == root.val:
+            return root
+        else:
+            root.left = self.insert(root.left, value)
+    
+    def successor(self, root):
+        # one step right and then all left
+        root = root.right
+        while root.left:
+            root = root.left
+        return root.value
+    
+    def predecessor(self, root):
+        # one step left and then always right
+        root = root.left
+        while root.right:
+            root = root.right
+        return root.value
+
+    def delete(self, root, key) -> TreeNode:
+        if not root:
+            return None
+
+        if key > root.val:
+            root.right = self.delete(root.right, key)
+        
+        elif key < root.val:
+            root.left = self.delete(root.left, key)
+        
+        else:
+            if not (root.left or root.right):
+                root = None
+            elif root.right:
+                root.val = self.sucessor(root)
+                root.right = self.delete(root.right, root.val)
+            else:
+                root.val = self.predecessor(root)
+                root.left = self.delete(root.left, root.val)
+        
+        return root
+