Find the diameter of a binary tree

Question

I am trying to find the diameter of a binary tree (Path length between any two nodes in the tree containing maximum number of nodes.) in java.

my code snippet:

Answer 1

I suggest the following:

public static TreeAttr calcTreeDiameter(Node root) {
    if (root == null)
        return new TreeAttr(0, 0);

    TreeAttr leftAttr = calcTreeDiameter(root.getLeft());
    TreeAttr rightAttr = calcTreeDiameter(root.getRight());

    int maxDepth = Math.max(leftAttr.depth, rightAttr.depth);
    int maxDiam = Math.max(leftAttr.diameter, rightAttr.diameter);
    maxDiam = Math.max(maxDiam, leftAttr.depth + rightAttr.depth + 1);

    return new TreeAttr(maxDiam, maxDepth + 1);
}

The TreeAttr is a simple structure containing the diameter and depth of a subtree. Both should be passed in the recursion, since the optimum may either come from one of the subtrees, or from the concatenation of the longest paths.