Given a binary tree, you need to compute 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.
Example:
Given a binary tree
1
/ \
2 3
/ \
4 5
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].
Note: The length of path between two nodes is represented by the number of edges between them.
class Solution:
def diameterOfBinaryTree(self, root: TreeNode) -> int:
if root is None:
return 0
return self.dc(root)[0] - 1
def dc(self, node):
if node is None:
return 0, 0, 0
if node.left is None and node.right is None:
return 1, 1, 1
l_maxpath, l_path, l_depth = self.dc(node.left)
r_maxpath, r_path, r_depth = self.dc(node.right)
depth = max(l_depth, r_depth) + 1
path = l_depth + 1 + r_depth
maxpath = max([path, l_maxpath, r_maxpath])
return maxpath, path, depth
# nodes on dia path = l_depth + 1 + right_depth