It was as follows:
(1) When I asked how I could be of service at LinkedIn, the interviewer could not answer the question, stating they were not sure whether I would be filling an entry-level role or a senior role.
(2) It was difficult to understand the interviewer’s accent.
(3) I was given the same question I was asked ten years ago: How do you test whether two binary trees are mirror images, for which the entry-level coder's answer would be something hideous like:
==============================================
bool isMirror(Node* tree1, Node* tree2)
{
bool ret_val = false;
if(tree1 != null && tree2 != null)
{
ret_val = (tree1->m_data == tree2->m_data) &&
isMirror(tree1->m_lhs, tree2->m_rhs) && isMirror(tree1->m_rhs, tree2->m_lhs);
}
return (tree1 == null && tree2 == null) ? true : tret_val;
}
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(4) The interviewer did not want an iterative solution that avoided stack overflows and made better use of CPU cache, much less a PhD with physics and maths skills.