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Program to find largest sum of any path of a binary tree in Python

Suppose we have a binary tree, we have to find the largest sum of any path that goes from the root node to the leaf node.

So, if the input is like

Program to find largest sum of any path of a binary tree in Python

then the output will be 29 as from root, if we follow the path 5-<9-<7-<8 it will be 29 after addition.

To solve this, we will follow these steps−

  • Define a function walk(). This will take node, s

  • if node is null, then

    • max_sum := maximum of max_sum and s

    • return

  • s := s + data of node

  • walk(left of node, s)

  • walk(right of node, s)

  • From the main method do the following−

  • max_sum := 0

  • walk(root, 0)

  • return max_sum

Let us see the following implementation to get better understanding−

Example

from collections import defaultdict
   class TreeNode:
      def __init__(self, data, left = None, right = None):
         self.data = data
         self.left = left
         self.right = right
   class Solution:
      def walk(self, node, s):
         if not node:
            self.max_sum = max(self.max_sum, s)
         return
      s += node.data
      self.walk(node.left, s)
      self.walk(node.right, s)
   def solve(self, root):
      self.max_sum = 0
      self.walk(root, 0)
   return self.max_sum
ob = Solution()
root = TreeNode(5)
root.left = TreeNode(1)
root.right = TreeNode(9)
root.right.left = TreeNode(7)
root.right.right = TreeNode(10)
root.right.left.left = TreeNode(6)
root.right.left.right = TreeNode(8)
print(ob.solve(root))

Input

root = TreeNode(5)
root.left = TreeNode(1)
root.right = TreeNode(9)
root.right.left = TreeNode(7)
root.right.right = TreeNode(10)
root.right.left.left = TreeNode(6)
root.right.left.right = TreeNode(8)

Output

29