Duplicate a Binary Tree

Question: Given a binary tree, write a program to duplicate the tree (i.e. create an exact copy of the tree).

Time Complexity: O(n)

tree *

tree_duplicate(tree *t) 

{

    tree *tmp = NULL;

    if (!t) {

        return NULL;

    }

    tmp = (tree *) malloc (sizeof(tree));

    if (!tmp) {

        exit(ENOMEM);

    }

    tmp->data = t->data;

    tmp->left = tree_duplicate(t->left);

    tmp->right = tree_duplicate(t->right);

    return (tmp);

}