From f20a475230f8f036710d40a7a9f613c4dc808789 Mon Sep 17 00:00:00 2001
From: Shinjanee Gupta <shinjaneegupta@gmail.com>
Date: Wed, 25 Feb 2026 17:33:01 -0800
Subject: [PATCH] completed Trees-2

---
 constructTree.py        | 32 ++++++++++++++++++++++++++++++++
 sumRootToLeafNumbers.py | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 constructTree.py
 create mode 100644 sumRootToLeafNumbers.py

diff --git a/constructTree.py b/constructTree.py
new file mode 100644
index 00000000..33a8dbf3
--- /dev/null
+++ b/constructTree.py
@@ -0,0 +1,32 @@
+# Time Complexity : O(n)
+# Space Complexity : O(n)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+# Approach : elements to the left and right of root in inorder array are used to form the left and right subtree.
+
+# 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, inorder: List[int], postorder: List[int]) -> Optional[TreeNode]:
+        def tree(left, right):
+            if left > right:
+                return None
+
+            root_val = postorder.pop()
+            root = TreeNode(root_val)
+
+            root.right = tree(inorder_idx_map[root_val] + 1, right)
+            root.left = tree(left, inorder_idx_map[root_val] - 1)
+
+            return root
+
+        inorder_idx_map = {}
+
+        for idx, val in enumerate(inorder):
+            inorder_idx_map[val] = idx
+
+        return tree(0, len(postorder) - 1)
\ No newline at end of file
diff --git a/sumRootToLeafNumbers.py b/sumRootToLeafNumbers.py
new file mode 100644
index 00000000..4ec03fd7
--- /dev/null
+++ b/sumRootToLeafNumbers.py
@@ -0,0 +1,33 @@
+# Time Complexity : O(n)
+# Space Complexity : O(n)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+# Approach : On reaching leaf node, return the number formed so far as it is a complete path.
+# Return the sum of results from left and right subtrees to get the final answer.
+
+# 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 helper(self, root: Optional[TreeNode], currNum: int) -> int:
+        if root == None:
+            return 0
+
+        currNum = currNum * 10 + root.val
+
+        if root.left is None and root.right is None:
+            return currNum
+
+        left = self.helper(root.left, currNum)
+        right = self.helper(root.right, currNum)
+
+        return left + right
+
+
+    def sumNumbers(self, root: Optional[TreeNode]) -> int:
+        return self.helper(root, 0)
+
+        
\ No newline at end of file