Counting nodes in a tree in Java

Question

First of all, I swear this is not homework, it\'s a question I was asked in an interview. I think I made a mess of it (though I did realise the solution requires recursion).

Answer 1

You can count the tree by traversing it many ways. Simply preorder traversal, the code would be (based on the functions you defined):

int count() {
    count = 1;
    if (this.getLeftChild() != null)
        count += this.getLeftChild().count();
    if (this.getRightChild() != null)
        count += this.getRightChild().count();
    return count;
}