https://leetcode.com/problems/delete-nodes-and-return-forest

medium/delete_nodes_and_return_forest.py

@@ -0,0 +1,24 @@
+# https://leetcode.com/problems/delete-nodes-and-return-forest
+from typing import List, Optional
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+class Solution:
+    def delNodes(self, root: Optional[TreeNode], to_delete: List[int]) -> List[TreeNode]:
+        to_delete_set = set(to_delete)
+        ret = []
+        def dfs(node: Optional[TreeNode], is_root: bool) -> Optional[TreeNode]:
+            if not node:
+                return None
+            is_deleted = node.val in to_delete_set
+            if is_root and not is_deleted:
+                ret.append(node)
+            node.left = dfs(node.left, is_deleted)
+            node.right = dfs(node.right, is_deleted)
+            return None if is_deleted else node
+        dfs(root, True)
+        return ret