The Online Assessment

The Hudson River Trading online assessment is a timed, auto-graded coding test, delivered on CodeSignal, and it is the first gate every engineering candidate clears before a human sees their name. You get roughly four problems and something on the order of seventy-five to a hundred and fifty minutes to solve them in C++ or Python. It is open book, meaning the language reference is available while you work, and the passing bar is full AC: every hidden test case green, not just the examples you can see. Interns, new grads, and experienced Software Engineer and Algorithm Developer applicants all sit a version of it.

That single gate feeds two different loops, so it helps to know which one you are on. The Software Engineer and Core Developer track builds low-latency trading infrastructure and interviews deep on C++ and systems internals afterward. The Algorithm Developer track sits closer to research and opens its later rounds with a probability screen. The online assessment comes first for both, and it grades the same thing either way: whether you can turn a dense problem into correct, efficient code under a clock. This lesson takes that assessment apart. The famous quantitative-brainteaser reputation belongs to the research track's phone screens and to pure trading roles, not here.

The Hudson River Trading angle

HRT's assessment is decided by hidden tests and speed, which means correctness, efficiency, and edge cases beat any clever one-liner. The habit that sinks people is chasing an elegant trick and calling the problem done when the visible cases go green. HRT scores on the cases you cannot see. A recent sitting handed out four problems worth three hundred points each, with twenty test cases per problem and ten of them hidden, and applicants who passed every visible case were still turned away. Read the whole prompt and build the input that breaks your own solution. Make sure the complexity holds at the top of the constraint range before you move on. The grade lives in the corners the examples never show.