Question

I am having trouble finding the smallest element of a binary search tree. I have some code finished, but it is not working.

public T getMinElement(TreeNode<T> node) {
    //TODO: implement this
    if (node == null){
        return null;
    }
     if (node.getLeftChild() == null){
        return (T) node;
     }
     else{
        return getMinElement(node);
  }
}

Answer 1

You were almost there! You just need to recurse on the left child of your binary search tree (always guaranteed to be smaller). Also you had some syntax errors, which I fixed.

public <T> T getMinElement(TreeNode<T> node) {
  if (node == null){
    return null;
  }
  if (node.getLeftChild() == null){
    return node.getData(); // or whatever your method is
  } else{
    return getMinElement(node.getLeftChild());
  }
}