Add solution for BTS: remove element

neetcode/binary_trees/delete_from_binary_tree/solution.py

@@ -0,0 +1,34 @@
+from typing import Optional
+
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def find_min(self, root) -> TreeNode:
+        cur = root
+        while cur and cur.left:
+            cur = cur.left
+        return cur
+
+    def deleteNode(self, root: Optional[TreeNode], key: int) -> Optional[TreeNode]:
+        if not root:
+            return None
+        if key < root.val:
+            root.left = self.deleteNode(root.left, key)
+        elif key > root.val:
+            root.right = self.deleteNode(root.right, key)
+        else:
+            if not root.right:
+                return root.left
+            elif not root.left:
+                return root.right
+            else:
+                min_node = self.find_min(root.right)
+                root.val = min_node.val
+                root.right = self.deleteNode(root.right, min_node.val)
+        return root