Program to find a tree by updating values with left and right subtree sum with itself in Python

Suppose we have a binary tree, we have to find the same tree but every node's value is replaced by its its value + all of the sums of its left and right subtrees.

So, if the input is like

then the output will be

To solve this, we will follow these steps −

• Define a function tree_sum() . This will take root of a tree

• if root is null, then

  • return 0

• data of root := tree_sum(left of root) + tree_sum(right of root) + data of root

• return data of root

• From the main method, do the following:

• tree_sum(root)

• return root

Let us see the following implementation to get better understanding −

Example

class TreeNode:    def __init__(self, data, left = None, right = None):       self.data = data       self.left = left       self.right = right def inorder(root):    if root:       inorder(root.left)       print(root.data, end = ', ')       inorder(root.right)     class Solution:    def solve(self, root):       def tree_sum(root: TreeNode):          if root is None:             return 0          root.data = tree_sum(root.left) + tree_sum(root.right) + root.data return root.data tree_sum(root) return root ob = Solution() root = TreeNode(2) root.left = TreeNode(3) root.right = TreeNode(4) root.left.left = TreeNode(9) root.left.right = TreeNode(7) ob.solve(root) inorder(root)

Input

root = TreeNode(12) root.left = TreeNode(8) root.right = TreeNode(15) root.left.left = TreeNode(3) root.left.right = TreeNode(10)

Output

9, 19, 7, 25, 4,