First, there was the coding test. The same two problems that everyone gets: the ternary tree and the string-to-integer conversion problems. The trick there seems to be that the unit tests they provide are not sufficient, so you can pass their unit tests without having a fully operable solution, and then you will fail. I wrote my own unit tests to validate other cases.

The next day, they let me know that I passed the test. The next step was a phone screen. It was a very good conversation, and the interviewer was very nice. The coding exercise was to write a function that detects the first non-repeating character in a char array, and to do so with only a single pass over the array. Unfortunately, I was a bit sloppy and nervous with the coding exercise in the online text editor. Even though I solved it with the time/space efficiency they were looking for, I'm sure the code had some syntax errors and was not as elegant as I would have liked.

They let me know the next day that they were not interested in talking with me further. It's tough getting back into the rhythm of solving little coding exercises in text editors within several minutes, as it bears no resemblance to the coding we do in our real jobs. However, it is the nature of the interview game, so more practice is the only thing you can do!

Write a function that detects the first non-repeating character in a char array. Do so with only a single pass over the array.