Find the maximum distance of a node in a binary tree | Recursive

Title: Finding the maximum distance of a node in a binary tree

Analysis: The furthest two points must be on a subtree with a node A as its root, and the path between them must pass through the root node A of that subtree. Therefore, the original problem is equivalent to "calculating the height and maximum of the Saozi right subtree for each node"

Reference: http://www.cppblog.com/flyinghearts/archive/2010/08/16/123543.html

PHP Implementation:

<?php/** * @author: Wusuopubupt * @date: 2013-10-25 * * Get the max distance between 2 nodes of a binary tree *
*/$max _distance = 0; $root = Array ("Data" =>1, "left" =>array ("Data" =>2, ' left ' =>array ("Data" =>4, "right" =>arra Y ("Data" =>7)), "Right" =>array ("Data" =>3, ' left ' =>array ("Data" =>5), "right" =& 

Gt;array ("Data" =>6));
Print_r ($root);
$len = Tree_height ($root, $max _distance);

Var_dump ($max _distance);
	function Make_node ($left, $right, $data) {$node = Array ("Left" + = $left, "right" + = $right, "data" = $data);
return $node;

};
	function Tree_height ($root,& $max _distance) {if ($root = = NULL) return-1;
	$left _height = 0;
	$right _height = 0;
	if (Isset ($root [' left '])) {$left _height = tree_height ($root [' left '], $max _distance) + 1;
	} if (Isset ($root [' right ')]) {$right _height = tree_height ($root [' right '], $max _distance) + 1; } $distance = $left _height + $right _height;
	if ($max _distance < $distance) {$max _distance = $distance; } return $left _height > $right _height?
$left _height: $right _height;


 }