[1] Implement binary search tree phonebook

KuznetsovYuM/docs/data/1-st-exercise/phonebook_structures.py

@@ -52,6 +52,8 @@ def linked_list_collect_all(head):
     return records
 
 
+
+#HASH
 def _hash_bucket_index(key, table_size):
     return hash(key) % table_size
 
@@ -88,13 +90,81 @@ def hash_table_collect_all(table):
     return all_records
 
 
-# Quick test
+#BST
+def _bst_new_node(name, phone):
+    return {'name': name, 'phone': phone, 'left': None, 'right': None}
+
+
+def bst_add(root, name, phone):
+    """Insert or update. Returns (possibly new) root."""
+    if root is None:
+        return _bst_new_node(name, phone)
+
+    if name == root['name']:
+        root['phone'] = phone
+    elif name < root['name']:
+        root['left'] = bst_add(root['left'], name, phone)
+    else:
+        root['right'] = bst_add(root['right'], name, phone)
+    return root
+
+
+def bst_find(root, name):
+    if root is None:
+        return None
+    if name == root['name']:
+        return root['phone']
+    elif name < root['name']:
+        return bst_find(root['left'], name)
+    else:
+        return bst_find(root['right'], name)
+
+
+def _bst_find_minimum(node):
+    while node['left'] is not None:
+        node = node['left']
+    return node
+
+
+def bst_remove(root, name):
+    if root is None:
+        return None
+
+    if name < root['name']:
+        root['left'] = bst_remove(root['left'], name)
+    elif name > root['name']:
+        root['right'] = bst_remove(root['right'], name)
+    else:
+        if root['left'] is None:
+            return root['right']
+        if root['right'] is None:
+            return root['left']
+
+        successor = _bst_find_minimum(root['right'])
+        root['name'] = successor['name']
+        root['phone'] = successor['phone']
+        root['right'] = bst_remove(root['right'], successor['name'])
+    return root
+
+
+def bst_collect_inorder(root):
+    result = []
+    def inorder(node):
+        if node is None:
+            return
+        inorder(node['left'])
+        result.append((node['name'], node['phone']))
+        inorder(node['right'])
+    inorder(root)
+    return result
+
+
 if __name__ == '__main__':
-    ht = hash_table_create(5)
-    ht = hash_table_put(ht, 'Alice', '111')
-    ht = hash_table_put(ht, 'Bob', '222')
-    ht = hash_table_put(ht, 'Alice', '333')
-    print(hash_table_get(ht, 'Alice'))   # 333
-    print(hash_table_get(ht, 'Charlie')) # None
-    ht = hash_table_remove(ht, 'Bob')
-    print(hash_table_collect_all(ht))    # [('Alice','333')]
+    tree = None
+    tree = bst_add(tree, 'Zoe', '111')
+    tree = bst_add(tree, 'Alice', '222')
+    tree = bst_add(tree, 'Bob', '333')
+    tree = bst_add(tree, 'Alice', '444')
+    print(bst_find(tree, 'Alice'))   # 444
+    tree = bst_remove(tree, 'Bob')
+    print(bst_collect_inorder(tree)) # [('Alice','444'), ('Zoe','111')]