construct-binary-tree-from-preorder-and-inorder-traversal solution

Author: sun912

construct-binary-tree-from-preorder-and-inorder-traversal/sun912.py

@@ -0,0 +1,19 @@
+"""
+TC: O(n)
+SC: O(n)
+"""
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def buildTree(self, preorder: List[int], inorder: List[int]) -> Optional[TreeNode]:
+        if inorder:
+            idx = inorder.index(preorder.pop(0))
+            node = TreeNode(inorder[idx])
+            node.left = self.buildTree(preorder, inorder[0:idx])
+            node.right = self.buildTree(preorder, inorder[idx+1:])
+
+            return node