Two rounds were conducted: one reviewer in the first, and four in the second.

In all cases, I was asked for a solution and tests. All tasks were written on the board.

The results of the interview rounds were very fast: the same day for the first one done via Skype, and the next day for the second one done on-site.

I had very little time for preparation (due to family and childcare issues, and I hadn't studied earlier as I wasn't actively looking for a new job), so my performance was far from stellar.

After the third reviewer on-site, I was pretty much sure I wouldn't get an offer.

You have a string input with text, where spaces between words were removed. You also have a method bool IsWord(string word) that returns true if the given string is a word. Your task is to return the sentence with restored spaces between words.

You have a method bool Perform(string inputA, string inputB, string Validation) that returns true if the Validation string contains both inputA and inputB (they can be interleaved). For example, Perform("ABC", "XYZ", "AXYBCZ") returns true.

You have the Ackermann function. I am actually not sure what the question was supposed to be, but the interviewer asked about the highest m, n values you can input without encountering a stack overflow error.

Code method bool IsPrimeNumber(int candidate).

You have a linked list. Determine whether there is a loop in the linked list, and identify the first cell in the linked list that is part of the loop.