I recently moved to Toronto and found myself in job search mode again. I interviewed at 3 different places and though I wouldn't say TopHat's was an absolute waste of time, it was the least pleasant.
The initial call was nice enough, though the second stage was algorithm and optimization focused. You should be fine if you're comfortable with HackerRank-like problems with optimizations and search-based algo problems, otherwise good luck. There's also a third on-site stage, though I can't speak to that experience.
The second person interviewing me clearly didn't want to be there, and gave no shits except for the most precise solution. Even though I produced correct answers and walked through my thought process, he kept pressing for something 'faster'. And no, I didn't nest a bunch of for loops.
https://github.com/mkubaczyk/helmsman