124. Binary Tree Maximum Path Sum - LeetCode Solution

# 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:
        self.ans = -float("inf")
        
        
        def trav(root):
            if not root:
                return 0
            
            left = trav(root.left)
            right = trav(root.right)
            
            temp = max(root.val, root.val + max(left, right) , root.val + left+right)
            
            self.ans = max(self.ans, temp)
            
            return max(root.val, root.val + left, root.val + right)
        
        trav(root)
        return self.ans