Binary tree

543. Diameter of Binary Tree

Given the root of a binary tree, return the length of the diameter of the tree.

The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.

The length of a path between two nodes is represented by the number of edges between them.

 # 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 diameterOfBinaryTree(self, root: Optional[TreeNode]) -> int:
        self.res=0
        self.solve(root)
        return self.res
        
    def solve(self,root):
        if not root:
            return 0
        l=self.solve(root.left)
        r=self.solve(root.right)
        
        temp=max(l,r)+1
        ans=l+r
        self.res=max(self.res,ans)
        return temp