feat: implement binary search tree

lomakinae/docs/data/01/src/bst.py

@@ -0,0 +1,65 @@
+def _bst_new_node(name, phone):
+    return {'name': name, 'phone': phone, 'left': None, 'right': None}
+
+
+def bst_insert(root, name, phone):
+    if root is None:
+        return _bst_new_node(name, phone)
+
+    if name == root['name']:
+        root['phone'] = phone
+    elif name < root['name']:
+        root['left'] = bst_insert(root['left'], name, phone)
+    else:
+        root['right'] = bst_insert(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_min_node(root):
+    node = root
+    while node['left'] is not None:
+        node = node['left']
+    return node
+
+
+def bst_delete(root, name):
+    if root is None:
+        return None
+
+    if name < root['name']:
+        root['left'] = bst_delete(root['left'], name)
+    elif name > root['name']:
+        root['right'] = bst_delete(root['right'], name)
+    else:
+        # node found — three cases
+        if root['left'] is None:
+            return root['right']
+        if root['right'] is None:
+            return root['left']
+
+        # two children: replace node with in-order successor
+        successor = _bst_min_node(root['right'])
+        root['name'] = successor['name']
+        root['phone'] = successor['phone']
+        root['right'] = bst_delete(root['right'], successor['name'])
+
+    return root
+
+
+def bst_list_all(root):
+    if root is None:
+        return []
+    return bst_list_all(root['left']) + [(root['name'], root['phone'])] + bst_list_all(root['right'])