Given a non-empty binary tree, find the maximum path sum.

For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The path must contain at least one node and does not need to go through the root.

Example 1:


Input: [1,2,3]

       1
      / \
     2   3

Output: 6


Example 2:


Input: [-10,9,20,null,null,15,7]

   -10
   / \
  9  20
    /  \
   15   7

Output: 42

Source: leetcode | Difficulty: MEDIUM_HARD
Tags: Tree algorithms

Dynamic programming

Graph traversal

Starter code: # 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 maxPathSum(self, root: TreeNode) -> int:
        

Solutions: