I've only taken the coding challenge with Hudson River. It's processed by Codility, which took 3 hours to solve 3 coding problems. The former two require using C++, and the last one could be written in any language of your choice.
Not allowed to share the code challenge, though.
The following metrics were computed from 19 interview experiences for the Hudson River Trading Software Engineer (Internship) role in United States.
Hudson River Trading's interview process for their Software Engineer (Internship) roles in the United States is extremely selective, failing the vast majority of engineers.
Candidates reported having good feelings for Hudson River Trading's Software Engineer (Internship) interview process in United States.