https://leetcode.com/problems/create-binary-tree-from-descriptions

medium/create_binary_tree_from_descriptions.py

@@ -0,0 +1,26 @@
+# https://leetcode.com/problems/create-binary-tree-from-descriptions
+from typing import Dict, 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 createBinaryTree(self, descriptions: List[List[int]]) -> Optional[TreeNode]:
+        nodes: Dict[int, TreeNode] = {}
+        s = set()
+        for head, next, left in descriptions:
+            if nodes.get(head) is None:
+                nodes[head] = TreeNode(head)
+            if nodes.get(next) is None:
+                nodes[next] = TreeNode(next)
+            if left:
+                nodes[head].left = nodes[next]
+            else:
+                nodes[head].right = nodes[next]
+            s.add(next)
+        for node in nodes:
+            if node not in s:
+                return nodes[node]
+