More specifically, this was for the role of NDIS Senior Software Developer. I received a HackerRank challenge with three questions and a 90-minute limit.

The input arguments to the questions were worded in a misleading way, and I had to use trial-and-error to determine the correct input and/or output data types.

I did fairly well, as determined by the number and percentage of passing tests, but I received a rejection email anyway.

Given a positive integer N, write a function to return a list of the first N Fibonacci numbers in order. For example, if N=5, the output list is 0, 1, 1, 2, 3.

Given a list of strings, return a list of strings of equal length. For each input string, if it is an IPv4 address, output "IPv4". If it is an IPv6 address, output "IPv6". If neither, output "Neither".

Given a list of integers A and an integer k, return the number of unique pairs of integers in A that sum to k. For example, if A=[1, 2, 5, 5, 10, 8, 2] and k=10, the answer is 2, arrived at by 5+5 or 2+8. There were 15 tests for this question, with at least the last two timing out, given that the implementation was not as efficient as possible.